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A  Review  of  the 

North  American  Species  of 

AGABUS 

Together  with  a  Description 

of  a  New  Genus  and 

Species   of  the 

Tribe  Agabini 

By  H.  C.  FALL 


MOUNT  VERNON,  N.  Y. 
JOHN  D.  SHERMAN,  JR. 

1922 


Copyright,  1922 

by 

John  D.  Sherman,  Jr. 


MAIN  UCRAP.Y-AOR  "C 


SOUTHWORTH  PRINTING  COMPANY,  PORTLAND,  MAINE 


A  Review  of  the  North  American 
Species  of  Agabus 

Together  with  a  Description  of 
a  New  Genus  and  Species  of  Agabini 

By  H.  C.  FALL 

The  genus  Agabus,  in  the  broad  sense  in  which  it  is  used  by  Sharp, 
and  to  which  American  students  have  become  accustomed,  includes, 
next  to  Hydroporus,  a  greater  number  of  species  than  any  other  genus 
of  North  American  Dytiscidae.  Not  since  the  appearance  of  Sharp's 
Monograph  in  1882  has  any  general  survey  of  our  Agabi  been  offered, 
and  the  arrangement  of  species  in  both  the  Henshaw  and  Leng  Lists 
is  substantially  in  accord  with  Sharp's  treatment. 

First  and  last  a  considerable  number  of  genera  have  been  established 
at  the  expense  of  Agabus,  most  of  which  are  rejected,  at  least  in  the 
full  generic  sense,  by  Sharp.  In  a  restricted  sense  nearly  all  our 
species  belong  to  Gaurodytes  of  C.  J.  Thomson,  under  which  name 
they  were  treated  by  Crotch  in  his  Revision  of  1873,  and  which  has 
recently  been  fully  accepted  by  Zimmermann.  Sharp  does  not  accept 
this  and  other  genera,  for,  as  he  says,  Thomson  "unfortunately  relied 
largely  on  one  (character)  which  is  very  unsuitable  for  the  purpose 'of 
arriving  at  a  natural  classification;  I  am  alluding  to  the  size  and 
form  of  the  wings  of  the  metasternum ;  so  variable  is  this  character 
that  scarcely  any  two  species  can  be  found  agreeing  as  to  it,  and 
on  the  other  hand,  species  which  are  nearly  or  quite  conformable  as  to 
this,  are  really  by  no  means  naturally  allied  by  their  other  characters." 
Of  typical  Agabus,  as  represented  by  the  serricornis  of  the  Palearctic 
fauna,  we  have  the  single  species  clavatus  Lee.,  which  like  serricornis 
is  remarkable  in  having  the  apical  joints  of  the  antennae  in  the  male 
dilated  and  compressed,  and  has  the  metasternal  laciniae  relatively 
narrow,  this  latter  character  however  being  less  extreme  in  clavatus 
than  in  serricornis.  Two  species — cordatus  and  rectus — peculiar  by 
the  small  nebrioid  form  of  thorax,  have  been  by  LeConte  and  Crotch 
referred  to  Anisomera  Brulle  founded  upon  a  Chilian  species  of  small 
size  and  flavate  color.  Although  quite  unacquainted  with  the  South 
American  insect,  this  reference  seems  to  me  extremely  questionable. 
It  is  probable  however  that  these  two  species  belong  to  Hydronebrius 


603964 


JakovL,  rated  by  Zimmermann  as  a  subgenus  of  Gaurodytes,  and  for 
the  present  I  content  myself  with  placing  them  at  the  head  of  our 
series  of  species,  where  they  constitute  a  very  distinct  group  of  prob- 
ably subgeneric  value. 

Sharp  regarded  the  genus  Agabus  as  one  "of  extreme  difficulty,  so 
far  as  regards  the  determination  of  species."  He  arranged  the  species 
in  twenty-three  groups,  "some  of  them  natural,  some  clearly  artificial," 
but  made  no  attempt  to  tabulate  either  the  groups  or  the  species  within 
them.  Zimmermann1  in  his  recent  work  declares  himself  completely 
baffled  in  his  attempts  to  define  natural  groups  in  Agabus  on  external 
characters,  but  he  has  established  three  sections  of  the  genus  based 
on  differences  in  the  genital  armature  in  the  males.  I  am  by  no  means 
certain  that  these  constitute  natural  groups,  in  fact  unless  there  has 
been  some  mistake  in  the  identification  of  our  species,  the  referring 
of  such  manifestly  closely  allied  forms  as  obsoletus  and  morosus  to 
different  sections  would  seem  to  militate  against  it.  I  shall  therefore 
for  the  present  not  attempt  the  subdivision  of  the  genus  into  groups, 
but  will  present  our  species  in  a  single  table,  the  mutual  relationships 
being  indicated  so  far  as  may  be  by  the  tabular  arrangement  and  by 
comments  in  the  text. 

After  eliminating  cordatus,  rectus  and  clavatus,  I  shall  follow  Sharp 
in  using  as  a  first  criterion  the  form  of  the  prosternal  process.  There 
is  really  no  well  marked  line  of  demarcation  anywhere  between  the 
broader  and  flatter  form  generally  characteristic  of  this  process  in  the 
species  at  the  beginning  of  the  table,  and  the  narrower  strongly  convex 
or  carinate  form  prevailing  further  along  in  the  series,  so  that  care 
must  be  taken  to  check  up  conclusions  by  means  of  correlative 
'characters,  while  a  few  correctly  determined  species  as  standards  of 
reference  will  be  of  material  service  to  the  student.  The  sexual 
modifications  of  the  male  pro-  and  mesotarsi,  more  especially  of  the 
protarsal  claws  are  of  much  importance  in  the  determination  of  species 
and  should  always  be  accurately  noted.  About  the  only  other  character 
used,  of  which  preliminary  mention  need  be  made,  is  the  sculpture 
of  the  elytral  surface.  This  consists  universally  of  a  reticulation,  of 
which  the  meshes  vary  greatly  in  size,  form  and  degree  of  uniformity 
in  the  different  species,  a  minutely  critical  examination  of  which  is 
necessary  for  the  successful  use  of  the  table,  and  which  will  always 
prove  of  the  highest  value  in  the  identification  of  the  rather  numerous 
species  which  to  the  casual  glance,  or  under  too  low  amplification, 
seem  monotonously  similar.  It  may  aid  in  the  interpretation  of  the 
descriptions  to  say  that  the  strongest  obtainable  simple  lens — a  one- 
fourth  inch  triplet — has  been  usd  in  my  own  study. 

iDie   Schwimmkafer   des   Deutschen   Entomologischen   Museums   zu    Berlin — Dahlem. 


In  the  preparation  of  the  present  paper  I  have  been  greatly  indebted 
to  my  friend  Mr.  John  D.  Sherman,  Jr.  for  the  privilege  of  unrestricted 
study  of  his  very  rich  collection,  and  for  the  loan  and  gift  of  speci- 
mens. Mr.  J.  B.  Wallis  of  Winnipeg  has  assisted  materially  with 
good  series  of  the  numerous  species  taken  by  him  in  various  parts 
of  Manitoba  and  British  Columbia.  To  Mr.  C.  A.  Frost,  Chas.  Liebeck 
and  Chas.  Dury,  I  am  indebted  for  material  contributed  with  equally 
good  will  if  in  lesser  numbers,  to  all  of  whom  I  wish  to  express 
sincere  appreciation.  I  have,  of  course,  carefully  examined  the  types 
in  the  Museum  of  Comparative  Zoology  at  Cambridge,  which  thanks  to 
the  courtesy  of  Dr.  Henshaw  and  Mr.  Banks  have  been  freely  available 
for  study;  while  Dr.  Lutz  and  Mr.  Mutchler  have  kindly  granted 
similar  privileges  with  the  Roberts  collection  in  the  American  Museum 
of  Natural  History.  To  Mr.  Arrow  of  the  British  Museum  I  owe 
especial  thanks  for  his  kindness  in  sending  to  me  for  examination 
one  of  Kirby's  original  specimens  of  A.  phaeopterus,  and  typical 
examples  of  several  of  Sharp's  species,  as  well  as  notes  made  at  my 
suggestion  on  other  species  which  could  not  be  sent  out  from  the 
museum.  The  types  of  all  new  species  herein  described,  unless  other- 
wise indicated  remain  in  my  own  collection,  which  contains  all  the 
species  here  recognized. 

Table  of  Species 

1 .  Prothorax  narrower  at  base  than  near  the  middle,  and  much  narrower 
than  the  base  of  the  elytra,  the  sides  strongly  discontinuous  with  those 

of  the  latter  2 

Prothorax  not  narrower  at  base  than  at  middle,  the  sides  commonly 
more  or  less  nearly  continuous  with  those  of  the  elytra 3 

2.  Prothorax  cordate,  the  sides  distinctly  sinuate  posteriorly,  head  more 

or  le^s  rufous  in  front  and  behind  (Montana  to  New  Mexico.) cordatus 

Prothorax  not  cordate,  less  narrowed  at  base,  the  sides  posteriorly 
not  or  only  just  perceptibly  sinuate;  head  entirely  black.  (Vancouver; 
Washington.)  rectus 

3.  Antennae  with  the  outer  joints  dilated  and  compressed  in  the  male .40 

Antennae  nearly  filiform,  alike  in  the  sexes 4 

4.  Prosternal  process  broad  and  flat,  rather  widely  margined  at  sides 
basally,  the  surface  somewhat  rugose;  basal  two  joints  only  of  pro- 
tarsus  clothed  beneath  with  glandular  hairs,  mesotasi  apparently  de- 
void of  such  hairs;  sides  of  prothorax  feebly  sinuate  at  the   front 
angles  in  the  female;  species  small   (6^4  nim.),  black,  densely  finely 

subgranosely  reticulate  and  opaque spinipes 

Prosternal  process  broad,  smooth  and  flatly  convex,  the  apex  acute  but 

not  finely  acuminate,  joints  1-3  of  the  four  anterior  tarsi  of  the  male 
clothed  with  glandular  hairs  as  in  all  the  species  that  follow ;  species 
strongly  shining,  deep  black  (often  brownish  black  in  planitus},  elytra 


with  more  or  less  distinct  sublateral  yellow  spot  or  vitta  behind  the 
middle;  hind  tibiae  without  row  of  punctures  along  inner  margin 
(except  amplus)  ;  size  moderate  to  large 5 

Prosternal  process  rather  broad  and  only  moderately  convex,  less 
broadly  expanded  than  in  the  preceding  species  and  never  with  di- 
lated side  margins,  its  tip  sharply  acuminate  (except  hypomelas)  ; 
elytral  reticulation  well  impressed  (less  conspicuously  so  in  hypo- 
mehs),  hind  tibiae  with  a  row  of  punctures  along  inner  margin; 
species  of  moderate  to  large  size,  deep  black  (except  hypomelas.) 9 

Prosternal  process  narrower,  varying  from  moderately  convex  to  an- 
gularly or  acutely  carinate  (except  arcticus,  in  which  the  prosternum 
is  virtually  flat)  '. 11 

5.  Prosternal  process  with  the  sides  more  broadly  margined  just  behind 
the  coxae;  elytra  with  sublateral  yellow  vitta  behind  the  middle  (ex- 
cept amplus)  ;  minute  punctules  of  the  elytra  occurring  on  the  reticu- 
lating lines  6 

Prosternal  process  with  side  margins  not  dilated  behind  the  coxae ; 
elytra  with  postmedian  and  subapical  sublateral  small  yellow  spots  of 
variable  distinctness ;  minute  punctules  of  the  elytra  occurring  within 

the  areolae  8 

6.  Protarsi  of  male  only  narrowly  dilated,  the  basal  joint  with  only  a 
small  apical  area  clothed  with  glandular  pubescence*  anterior  protarsal 

claw  of  male  with  ante-basal  tooth.     (Ontario  to  Arizona.) semivittatus 

Protarsi  of  male  very  distinctly  widened,  the  basal  joint  clothed  be- 
neath with  glandular  pubescence  in  fully  the  apical  half 7 

7.  Meshes  of  elytral  reticulation  very  small  and  subequal,  either  through- 
out or  excepting  only  a  narrow  baso-sutural  area ;  anterior  protarsal 
claw  of  male  with  a  large  angulate  basal    lobe,  the  posterior    claw 

broader  but  not  lobed  at  base  (Florida.) johannis 

Meshes  of  elytral  reticulation  irregular  in  form  and  more  or  less  un- 
equal almost  or  quite  throughout. 

Anterior  protarsal  claw  of  male  with  a  strong  rectangular  basal 
dilatation ;  hind  tibiae  without  a  row  of  punctures  along  the  inner 

margin  (Pennsylvania;  North  Carolina.) stagninus 

Anterior  protarsal  claw  of  male  arcuately  thickened  post-medial- 
ly; elytra  with  a  small  sublateral  yellow  spot  behind  the  middle; 
hind  tibiae  with  a  series  of  four  to  six  punctures  along  the  inner 
margin.  Length  11.5  mm.  (Kentucky;  Missouri.) amplus 

8.  Side  margins  of  thorax  rather  narrow.     (Canada  and  Northeastern 

States.)    . obtusatus 

Side   margins   of   prothorax  notably  broad.      (Massachusetts;    Long 
Island.) planatus 

9.  Fine  punctures  of  the  elytra  occurring  at  the  intersections  of  the  retic- 
ulations;   metasternal  groove   unusually    short;   color    piceous    with 

brownish  margins.      (Alaska  to  Vancouver.) hypomelas 

Fine  punctures  of  the  elytra  very  minute  and  occurring  within  the 
meshes  of  the  reticulation ;  metasternal  groove  well  developed ;  color 
black,  side  margins  not  paler 10 


10.  Least  distance  between  middle  coxae  and  coxal  plates  less  than  half 
the  length  of  the  latter   (measured  along  a  continuation  of  the  same 
line.) 

Punctures  along  inner  margin  of  hind  tibia  well  separated;  size 
smaller   (8  to  9  mm.)     Greater  portion  of  Northern  U.  S.  and 

Canada.) seriatus 

Punctures  along  inner  margin  of  hind  tibia  so  close  set  as  to  form 
a  continuous  groove;  size  larger  (loto  n  mm.).    (California)   brevicollis 
Least  distance  between  middle  coxae  and  coxal  plates  rather  more 
than  half  the  length  of  the  latter;  elytra  with  small  sub-lateral  yel- 
low spot  behind  the  middle.     (Rocky  Mountains  to  Pacific  Coast.)      lugens 
Form  a  little  more  obtuse,  reticulation  coarser var.  perplexus 

1 1.  Inner  apical  spur  of  hind  tibia  longer  than  the  basal  joint  of  the  tarsus 12 

Inner  apical  spur  of  hind  tibia  never  longer,  usually  distinctly  shorter 
than  the  basal  joint  of  the  tarsus 13 

12.  Long  spur  of  hind  tibia  stouter  and  more  abruptly  pointed  at  tip  in 
the  male  than  in  the  female;  intermediate  legs  of  male  unmodified; 

four  anterior  tarsi  of  male  distinctly  pubescent  beneath punctatus 

Long  spur  of  hind  tibia  similar  in  the  sexes  and  very  gradually  point- 
ed ;  middle  femora  of  male  fimbriate  with  long  hairs  on  the  posterior 
margin;  middle  tibiae  (o*)  with  a  fringe  of  shorter  hairs  on  the  inner 
margin;  four  anterior  tarsi  (c?)  very  feebly  thickened  and  with  very 
little  glandular  pubescence  beneath aeruginosus 

13.  Anterior  protarsal  claw  of  male  rather  broad    and    of    equal  width 
throughout,  the  tip  nearly  squarely  truncate;  both  claws  shorter  than 

usual    triton 

Anterior  protarsal  claw  of  male  conspicuously  toothed  beneath;  very 
small    species,  rarely  (semipunctatus)  attaining   a    length  of  7  mm. ; 

elytra  not  vittate 14 

Anterior  protarsal  claw  of  male  with  a  small  tooth  near  the  base; 

elytra  yellow  with  black  vittae  1 

Anterior  protarsal  claw  of  male  not  toothed  beneath  (except  lutosus 

and  griseipennis,  in  both  of  which  the  anterior  tarsi  are  extremely 
widely  dilated),  the  tip  normally  acute 16 

14.  Surface    distinctly  aeneous;    the   elytra   usually    paler,    brownish   to 
brownish  piceous. 

Apex  of  ungual  tooth  subapical  in  position;  form  of  body  more 

oval punctulatus 

Apex  of  ungual  tooth  median  in  position ;   body  narrower  and 

more  oblong  oblongulus 

Surface  not  aeneous,  color  black. 

Abdomen  without  sexual  modification,  side  margins  of  prothorax 

rather   broad sharpi 

Abdomen  of  male  with  a  system  of  parallel  rugae  on  the  third 
segment,  side  margins  of  thorax  appreciably  narrower.... semipunctatus 

15.  Prothorax  yellow  with  basal  and  apical  margins  blade  except  at  sides; 
meshes  of  elytral  reticulation  almost  completely  impunctate,  but  with 


a  few  fine  punctures  at  the  intersections  of  the  reticulating  lines  in 

taeniolatus. 

Body  red  beneath;  basal  joint  of  middle  tarsus  of  male  as  long  as 

that  of  the  hind  tarsus taeniolatus 

Body  beneath  in  part  pale,  the  metasternum  and  coxal  plates 
black;  basal  joint  of  middle  tarsus  of  male  much  shorter  than 
that  of  the  hind  tarsus disintegrate 

Prothorax  piceous  with  side  margins  pale,  varying  to  entirely  pale; 

body  beneath  black;  meshes  of  elytra!  reticulation  larger  and  as  a  rule 

each  with  one  or  more  fine  punctures . lineellus 

16.  Lower  face  of  hind  tibiae  without  a  series  of  punctures  along  the 
inner  margin  or  at  most  with  only  a  few  punctures  near  the  base  or  in 
basal  half;  accessory  discal  tibial  punctures  few  or  lacking  (Infusca- 
tus  and  some  examples  of  bicolor  are  exceptions  in  that  they  have  a 
loose  series  of  punctures  along  the  inner  margin,  they  however  lack 

the  intermediate  discal  punctures *  • 

Lower  face  of  hind  tibiae  with  a  row  of  punctures  along  the  inner 
margin,  usually  extending  from  base  nearly  or  quite  to  apex 33 

17.  Elytra  coarsely  reticulate  in  both  sexes 18 

Elytra  finely  or  minutely  reticulate  in  the  male,  the    females   more 
coarsely  so  in  some  species 20 

18.  Reddish  brown,  metasternum  and  coxal  plates  blackish austini 

Black,  elytra  brownish  or  fuscous 19 

Size  small  (less  than  7  mm.)  ;  form  narrowly  oval strigulosus 

Size  larger  (8  mm.  or  more)  ;  form  more  broadly  oval. 

Prosternal  claws  of  male  slender  and  elongate,  the  posterior  one 
feebly  sinuate  beneath;  elytral  sculpture  not  materially  different 
in  the  sexes,  the  female  usually  a  little  duller ambiguus 

Prosternal  claws  of  male  foliately  expanded;  elytral  reticulation 
strongly  longitudinal  basally  in  the  female erythropterus 

20.  Meshes  of  elytral  reticulation  more  or  less  irregular  and  unequal,  at 
least  baso-medially   21 

Meshes  of  elytral  reticulation  very  minute,  more  rounded,  and  every- 
where nearly  equal  ...29 

21.  Protarsi  of  male  very  widely  dilated,  basal  joint  scarcely  as  wide  as 
the  second,  the  third  joint  fully  twice  as  wide  as  the  fourth;  anterior 
protarsal  claw  of  male  dentate 22 

Protarsi  of  male  less  widely  to  very  feebly  dilated,  basal  joint  wider 
than  the  second;  male  anterior  claw  not  toothed 23 

22.  Tooth  of  anterior  protarsal  claw  in  male  nearly  median  in  position; 
meshes  of  elytral  reticulation  more  unequal.     (Vancouver  to  Southern 
California.)    lutosus 

Tooth  of  anterior  protarsal  claw  subapical  in  position,  making  the 
claw  appear  almost  bifid;  male  protarsus  extremely  broad;  meshes  of 
elytral  reticulation*  rather  smaller  and  more  nearly  equal.  (Wyoming 
to  Nevada  )  griseipennis 

6 


23.  Protarsi  of  male  rather  strongly  dilated,   the  third  joint  evidently 
wider  than  the  fourth  though  much  less  than  twice  as  wide;  pro- 
tarsal  claws  of  male  more  elongate  and  quite  distinctly  sinuate;  epi- 

pleura  in  great  part  blackish  or  piceous  (except  nigripalpis.) 24 

Protarsi  of  male  feebly  dilated,  the  third  joint  scarcely  or  only  just 
visibly  wider  than  the  fourth,  the  claws  slender  and  only  just  per- 
ceptibly sinuate  beneath ;  epipleura  pale 26 

24.  Last  palpal  joint  entirely  or  in  great  part  black;  form  narrower  and 

slightly  obovate.     (Arctic  America  and  Siberia.) nigripalpis 

Last  palpal  joint  entirely  testaceous,  or  at  most  a  little  infuscate  api- 
cally;  form  broader,  size  larger 25 

25.  Epipleura  entirely  dark.     (Vancouver  to  South  California.) morosus 

Epipleura  blackish  internally,  the  outer  margin  pale. 

Size  smaller    (less  than  7  mm.)  ;   form  more  obtusely  rounded 

anteriorly.      (Oregon.)    , ancillus 

Size  larger  (7  to  8  mm.)  ;  form  more  oval.     (Rocky  Mts. ) ... .obliteratus 

26.  Elytral  reticulation  less  fine,  the  meshes  obviously  unequal  and  of 
irregular  form  almost  throughout,  becoming  nearly  equal  only  at  the 
extreme  apex ;  distance  between  mesocoxal  cavities  and  coxal  plates 

equal  to  or  greater  than  half  the  length  of  the  latter 27 

Elytral  reticulation  more  minute,  the  meshes  unequal  on  close  exami- 
nation baso-medially,  but  becoming  nearly  equal  toward  the  sides  and 
apex;  outer  joints  of  antennae  and  palpi  without  or  with  only  faint 
infuscation    28 

27.  Apices  of  outer  joints  of  antennae,  and  apical  half  or  more  of  ter- 
minal joints  of  palpi  blackish;  prosternal  process  arcuately  convex  in 

cross  section ;  form  more  elongate congener 

Antennae  and  palpi  without  appreciable  infuscation;  prosternal  proc- 
ess narrower  and  strongly  angulate  or  compresso-carinate ;   form  a 
little  broader  approximatus 

28.  Metasternal   wings   shorter,  the  distance   separating  the  meso-coxal 
cavity  from  the  coxal  plate  less  than  half  the  length  of  the  latter; 

prosternal  process  rather  less  narrow  and  less  convex discolor 

Metasternal  wings  longer,  the  coxal  plate  distant  from  the  meso-coxal 
cavity  by  about  half  its  own  length;  prosternal  process  rather  nar- 
rower and  more  strongly  convex inscriptus 

29.  Prosternal  process  arcuately  to  subangularly  convex  in  cross  section 30 

Prosternal  process  abruptly  acutely  carinate  along  the  middle 32 

30.  Sides  of  prothorax  conspicuously  pale;  claws  of  male  protarsi  larger 

and  more  strongly  sinuate canadensis 

Sides  of  prothorax  not  at  all  or  only  extremely  narrowly  and  vaguely 
paler 31 

31.  Posterior  protarsal  claw  of  the  male  obtusely  subangulate  at  about 
one-third  from  the  tip,  the  anterior  claw  feebly  sinuate  on  its  inner 
edge;  metasternal  wings  a  little  broader    (in  a  longitudinal  sense.) 

subfuscatus 

Posterior  protarsal  claw  feebly  sinuate  toward  the  base,  the  anterior 

one  scarcely  so ;  metasternal  wings  a  little  narrower. 


Elytra  dark  brown  to  yellowish  brown,  thorax  black phaeopterus 

Elytra  nearly  black  like  the  thorax,  the  margins  only  narrowly 
brownish bicolor 

32.  Male  protarsi  very  feebly  dilated,  and  with  small  palettes  beneath; 
intralinear  area  of  hind  coxae  not  rugose . confinis 

Male  protarsi  rather  broadly  dilated,  with  large  palettes  beneath;  in- 
tralinear area  of  hind  coxae  rugose infuscatus 

33.  Prosternal  process  flat,  the  surface  a  little  concave  at  the  point  of 
maximum  width;  side  margins  of  the  thorax  in  the  female  sinuate  at 
front  angles ;  color  above  brownish  fuscous,  with  sides  and  transverse 
median  fascia  or  entire  apical  half  of  thorax,  and  side  margins  of 

elytra,  testaceous ., arcticus 

Prosternal  process  not  flat,  sides  of  thorax  not  sinuate  anteriorly  in 

the   female   :....- 34 

34.  Meshes  of  elytral  reticulation  very  small,  rounded,  and  subequal  (ex- 
cept in  part  in  ontarionis.) .. , 35 

Meshes  of  elytral  reticulation  much  larger,  irregular  and  unequal,  and 
showing  within  themselves  a  secondary  system  of  minute  reticulation 
most  noticeable  toward  the  sides  and  apex,  and  as  a  rule  more  evident 

in  the   females;   color  black  or  blackish  throughout    (except   tristis, 
which  varies  from  brown  to  nearly  black.) 36 

35.  Color  blackish  brown,  the  prothorax  nearly  black  except  the  side  mar- 
gins;   protarsal   claws   of     male     elongate,    nearly    straight,    sinuate, 

equal,  claw  joint  not  toothed  beneath ontarionis 

Color  above  and  beneath  dull  brownish  testaceous,  or  yellowish  brown. 

Protarsal  claws  of  male  elongate,  equal,  the  claw  joint  dentate 
beneath ajax 

Protarsal  claws  of  male  very  unequal,  the  anterior  scarcely  half 

the  length  of  the  posterior coxalis 

36.  Pro-  and  mesotarsi  of  male  with  extremely  large  circular  palettes  be- 
neath; metasternal  groove  long;  size  rather  small  or  moderate  (7  to 

8  mm.)   . anthracinus 

Pro-  and  mesotarsi  of  male  with  much  smaller  though  quite  distinct 
palettes;  metasternal  groove  short,  rudimentary;  size  large   (9  to  n 

mm.) nigroaeneus 

Pro-  and  mesotarsi  of  male  without  distinct  palettes  beneath 37 

37.  Meshes  of  elytral  reticulation  not  longitudinal    (sometimes  oblique 

basally  in  the  female  of  tristis.} 38 

Meshes  of  elytral  reticulation  wholly  or  in  great  part  strongly  elongate 
(less  conspicuously  so  in  the  male  of  leptapsis.) 39 

38.  Metasternal  groove  rudimentary;  middle    coxae   narrowly  separated 

confertus 

Metasternal  groove  well  developed,  subhorizontal ;  mesocoxae  less  ap- 
proximate. 

Form  rather  broadly  oval,  color  black,  size  smaller  (8  to  9  mm.) 

gagates 

Form  elongate  oval,  color  brownish    to    blackish    fuscous,   size 
larger  (gl/2  to  iQl/2  mm.) :. tristis 

8 


39.  Side  margins  of  prothorax  rather  narrow;  coxal  plates  distant  from 

the  mesocoxal  cavities  by  fully  half  their  own  length leptapsis 

Side  margins  of    prothorax    very  broad;    coxal  plates  distant  from 
mesocoxal  cavities  by  much  less  than  half  their  own  length discors 

40.  Rufo-  or  brownish  testaceous    elytra    a    little    darker;   coxal  plates 
large;  metasternal  wings  sublinear — length  about  7/^2  mm.;  (Nebraska 

to  British  Columbia.) .' clavatus 

A.  cordatus  Lee.     Proc.  Acad.  Nat.  Sci.  Phila.,  1853,  p.  226. 

Very  easily  recognized  by  the  small  subcordiform  thorax,  which  is  not  approached 
by  any  other  of  our  species  except  rectus.  The  color  is  not  truly  black,  the  upper 
surface  being  rather  piceous,  obscurely  tinged  with  rufous,  and  feebly  aenescent. 
The  four  anterior  tarsi  of  the  male  are  moderately  dilated,  the  protarsal  claws 
not  sexually  modified.  Length  8.7  to  9.2  mm. 

A  not  uncommon  species  in  the  Rocky  Mountain  Region,  and  known 
to  me  from  Montana  (Missoula)  ;  Colorado  (Colorado  Springs  and 
Leadville)  ;  New  Mexico  (Pecos)  ;  and  Utah  (Ft.  Douglas).  The 
type  is  from  Santa  Fe,  New  Mexico. 

A.  rectus  Lee.     Annals  Mag.  Nat.  Hist.  (4)  IV,  1869,  p.  375. 

Closely  similar  in  general  aspect  to  cordatus,  but  the  prothorax  is  scarcely  cordi- 
form,  the  sides  less  convergent  and  nearly  straight  posteriorly.  The  color  is  more 
truly  black,  the  upper  surface  entirely  devoid  of  rufous  marks  or  shades  in  the 
few  examples  seen.  Length  9  mm. 

This  is  a  distinctly  rarer  insect  in  collections  than  the  preceding.  It 
was  described  from  Vancouver,  and  is  known  to  me  also  from  Wash- 
ington State  (Wawawei — M.  C.  Lane). 

A.  spinipes  Sharp.     Biol.  C.  Am.  I,  2,  p.  32. 

Moderately  broadly  oval,  subdepressed,  outline  of  thorax  and  elytra  nearly  con- 
tinuous ;  black,  opaque ;  labrum,  clypeal  margin,  two  obscure  vertex  spots,  mouth, 
antennae  and  legs,  rufous.  Surface  densely  deeply  reticulate,  the  meshes  small, 
variable  in  form  and  size,  and  in  part  on  the  elytra  having  the  appearance  of 
small  flattened  granules.  Head  two-thirds  as  wide  as  the  prothorax,  the  latter  rath- 
er more  than  twice  as  wide  as  long,  distinctly  lobed  at  base,  lateral  bead  rufescent, 
sides  sinuate  at  front  angles  in  the  female.  Elytra  seven-tenths  as  wide  as  long, 
sides  evenly  arcuate,  apex  obtusely  rounded,  each  with  the  usual  series  of  coarser 
punctures;  minute  punctulation  indistinct  because  of  the  density  and  roughness 
of  the  reticulation.  Antennae  short  and  rather  thick,  the  intermediate  joints  only 
about  one-third  longer  than  wide.  Prosternal  process  broad,  feebly  convex  or 
flattened,  widely  margined,  the  apex  bluntly  acute ;  metasternal  wings  rather  wide 
between  the  middle  coxae  and  coxal  plates.  Sculpture  beneath  and  legs  much  as 
usual,  the  hind  tibiae  with  a  row  of  coarse  elongate  punctures  along  the  inner 
margin.  Male  with  anterior  tarsi  a  little  dilated  basally,  the  first  and  second 
joints  only  clothed  beneath  with  glandular  hairs,  which  are  tipped  with  small 
palettes;  the  middle  tarsi  undilated  and  quite  devoid  of  sexual  pubescence;  pro- 
tarsal claws  not  perceptibly  modified;  no  sexual  difference  in  surface  sculpture. 
Length  6.8  mm. ;  width  3.5  mm. 


Of  this  remarkable  species  there  is  a  male  specimen  in  my  own 
collection  from  the  Huachuca  Mts.,  Arizona.  Two  examples  (c?$)  in 
the  Sherman  collection,  and  a  third  example  in  the  Roberts  collection, 
all  from  the  Organ  Mts.,  New  Mexico,  agree  in  all  essential  characters, 
but  vary  in  having  the  surface  feebly  aenescent,  the  elytra  each  with  a 
vague  longitudinal  sulcus  between  the  rows  of  coarser  discal  punctures, 
the  latter  being  more  distinct  than  in  my  specimen  and  the  prosternal 
process  flat  or  a  little  impressed  and  more  or  less  rugose  at  its  broadest 
part. 

This  small  opaque  species  is  peculiar  in  its  unusually  short  and 
stout  antennae  and  broad  prosternal  process,  and  quite  unique  in  its 
limited  sexual  clothing  of  the  male  tarsi.  The  metatarsal  claws  are 
similar  to,  and  quite  as  large  as  those  of  the  pro-  and  mesotarsi. 

A.  semivittatus  Lee.     Ann.  Lye.  Nat.  Hist.,  New  York,  1851,  p.  204. 
tetanus  Shp.     On  Dytiscidae  p.  505. 

A  strongly  shining  black  species  of  medium  size,  the  elytra  with  a  sublateral  yel- 
low vitta  in  nearly  the  posterior  half,  which  is,  however,  sometimes  interrupted 
or  quite  obscure.  Elytral  reticulation  fine  and  feeble,  the  areolae  unequal  and  of 
irregular  form.  All  the  essential  characters  are  set  forth  in  the  table  of  species. 
The  very  broad  flattish  prosternal  process,  itself  widely  margined  for  some  dis- 
tance behind  the  coxae,  combined  with  the  very  small  area  of  the  basal  tarsal 
joint  clothed  with  glandular  hairs  in  the  male  afford  a  reliable  means  of  identifi- 
cation. The  four  anterior  tarsi  are  only  just  visibly  dilated  in  the  male,  the  pads 
of  adhesive  pubescence  narrow  and  densely  set  with  moderately  small  pallettes. 
Length  7.5  to  8.8  mm. 

Semivittatus  is  widely  dispersed  in  the  great  interior  region  of  the 
continent  but  seems  not  to  attain  the  coast  line  of  either  the  Atlantic 
or  the  Pacific.  Specimens  have  been  seen  from  Ontario,  Canada; 
Ohio  (Cincinnati)  ;  Illinois  (Edgebrook)  ;  Nebraska  (Malcom  and 
Kearney)  ;  Louisiana  (Winnfield) ;  Texas  (Waco) ;  Colorado 
(Boulder);  New  Mexico  (Las  Vegas);  Arizona  (Tucson). 

Some  examples,  more  especially  those  from  Texas  and  the  southwest 
are  a  little  less  evenly  oval  than  the  typical  form  of  the  species,  but  the 
difference  is  extremely  illusory  and  seems  not  to  be  supported  by  any 
structural  characters.  It  is  probable  that  the  type  of  texanus  Shp.  is 
one  of  these  slight  variants ;  Sharp's  description  however  fits  just 
as  well  in  all  respects  the  typical  semivittatus,  and  I  can  see  no  reason 
for  giving  te.ranus  even  varietal  standing.  The  semivittatus  of  Sharp's 
monograph  is  not  the  species  so  named  by  LeConte,  but  a  quite  distinct 
species  which  is  described  below. 

A.  johannis  new  species. 

This  name  is  proposed  for  the  Agabus  semivittatus  Lee.  of  Sharp's 
monograph.  Knowing  the  true  semivittatus  of  LeConte,  it  was  at 

10 


once  evident  from  Sharp's  description  of  the  male  protarsal  claws 
that  he  had  something  quite  different  in  hand.  The  original  of  Sharp's 
description  is  now  before  me  and  may  be  briefly  characterized  as 
follows. 

Rather  larger  but  precisely  similar  in  horizontal  outline  to  texanus  Shp.,  but  dis- 
tinctly more  strongly  convex  in  profile :  color  shining  black,  with  a  sublateral 
posterior  yellow  vitta  of  variable  distinctness;  hind  margin  of  prothorax  broadly 
subangularly  rounded  at  middle  (broadly  evenly  arcuate  in  semi-vittatus}  ;  elytral 
reticulation  very  fine,  meshes  very  small  and  subequal  throughout,  the  minute 
punctulation  evenly  distributed  and  distinct  under  sufficient  amplification :  protarsi 
of  male  rather  feebly  dilated  but  quite  strongly  compressed,  the  glandular  pubes- 
cence beginning  at  about  the  middle  of  the  basal  joint;  claws  rather  short,  the 
anterior  one  with  a  strong  angulate  basal  lobe,  the  posterior  one  broader  but  not 
lobed  at  base.  Length  8.5  to  9  mm. 

In  semivittatus  and  stagninus  the  elytral  reticulations  are  unequal 
and  quite  irregular  in  form  and  much  less  minute,  the  fine  punctules 
excessively  small  and  few  in  number. 

Described  from  four  examples  (30?,  i?)  from  the  British  Museum, 
two  of  which  bear  the  label  "St.  John's  Bluff,  E.  Florida."  The 
other  two  are  probably  from  the  same  source  though  carrying  no 
locality  label  other  than  "Am.  bor." 

Since  writing  the  above  I  have  received  three  examples  (2c?'s  i?) 
from  Mr.  W.  S.  Blatchley,  collected  by  him  at  Dunedin  on  the  West 
Florida  Coast  ("2-22-22").  The  male  tarsal  characters  are  precisely 
as  in  the  East  Florida  type  and  there  can  be  no  doubt  of  their  identity. 
The  Dunedin  specimens  differ  however  in  having  the  meshes  of  the 
elytra  in  the  baso-sutural  region  distinctly  unequal  while  in  the 
female  this  inequality  extends  throughout  the  surface,  the  reticulating 
lines  deeper  and  the  surface  less  shining. 

The  type  of  johannis  is  returned  to  the  British  Museum ;  paratypes 
in  my  own  collection  include  one  male  ("Am.  bor")  from  the  Sharp 
collection  and  the  three  Dunedin  specimens  mentioned. 

A.  stagninus  Say,  Trans.  Am.  Phil.  Soc.  II,  1825,  p.  100. 
ttriola  Aube,  Spec.  Gen.,  1838,  p.  308. 

Extremely  similar  in  nearly  every  feature  to  semivittatus,  but  of  somewhat 
larger  size,  and  distinguishable  with  certainty  by  the  male  tarsal  characters.  The 
anterior  tarsi  of  the  male  are  here  quite  distinctly  dilated,  the  glandular  hairs 
covering  the  apical  half  of  the  basal  joint  beneath  as  is  usual.  The  front  claw 
of  the  protarsus  is  not  toothed,  but  the  strong  rectangular  basal  angulation  is 
much  more  conspicuous  than  in  semivittatus.  As  in  the  latter  species,  the  ex- 
tremely minute  punctures  occur  on,  and  usually  at  the  intersections  of  the  reticu- 
lating lines,  and  not  within  the  areolae.  Length  9.2  to  10  mm. 

This  species  is  far  moie  restricted  in  range  than  semwittatus.  It  is 
personally  known  to  me  only  from  Pennsylvania  (Harrisburg),  New 
Jersey  (Anglesea),  and  North  Carolina.  It  is  given  in  the  South- 

ii 


western  Pennsylvania  and  Washington  Lists,  but  does  not  appear  in 
the  New  Jersey  List. 

A.  amplus  new  species. 

Size  large,  form  regularly  ovo-elliptical,  the  prothorax  and  elytra  perfectly  con- 
tinuous in  outline.  Color  black,  moderately  shining,  faintly  aenescent,  elytra  with 
a  small  sublateral  yellow  spot  behind  the  middle ;  mouth,  antennae  and  legs  dark 
rufous,  body  beneath  rufopiceous.  Head  nearly  two-thirds  as  wide  as  the  pro- 
thorax,  the  latter  more  than  twice  as  wide  as  long,  side  margins  unusually  broad. 
Reticulation  of  upper  surface  moderately  fine,  the  areolae  irregular  and  unequal, 
the  reticulating  lines  with  numerous  fine  punctures  which  occur  for  the  most  part 
at  the  intersections.  Coxal  plates  large,  the  length  of  the  metasternum  between 
them  and  the  mesocoxal  cavities  only  about  one-third  their  own  length.  Hind 
tibiae  with  a  row  of  five  or  six  punctures  along  the  inner  margin.  Pro-  and 
mesotarsi  of  male  quite  distinctly  dilated  and  rather  strongly  compressed,  the 
anterior  protarsal  claw  thickened  and  sinuate  beneath  but  without  tooth.  Length 
11.5  mm.;  width  6.25  mm. 

Described  from  a  single  pair,  submitted  by  Mr.  Sherman.  The  male 
type  retained  in  the  Sherman  collection  is  from  Missouri :  it  was 
obtained  from  Oberthur  and  bears  the  name  "brevicollis  Lee"  in 
Oberthiir's  hand.  The  female  bears  label  "Kentucky,  Sanborn." 

Our  largest  species  of  Agabus  and  evidently  quite  a  rarity.  In  addi- 
tion to  the  tabular  characters  it  may  be  distinguished  from  its  nearest 
allies  by  the  more  broadly  margined  thorax.  In  neither  of  the  two 
specimens  at  hand  is  there  any  trace  of  the  rufous  occipital  spots  which 
are  normally  present  in  stagninus  and  semivittatus  though  sometimes 
quite  obscure. 

A.  obtusatus  Say,  Trans.  Am.  Phil.  Soc.  II,  1823,  p.  99. 
?  nitidus  Say,  1.  c.  p.  98. 

Broadly  obtusely  oval,  polished  black,  elytra  with  apical  and  postmedian  sublateral 
yellow  spots.  The  lines  of  the  elytral  reticulation  are  very  fine  and  lightly  im- 
pressed, the  areolae  large,  irregular,  unequal,  and  each  as  a  rule  with  one  or  more 
minute  punctules.  The  length  of  the  metasternum  between  the  middle  coxae  and 
the  coxal  plates  is  scarcely  more  than  one-fourth  of  the  length  of  the  latter.  The 
male  tarsi  are  only  narrowly  incrassate,  the  protarsal  claws  virtually  unmodified, 
though  on  close  inspection  the  anterior  one  may  be  seen  to  be  faintly  sinuate  be- 
neath. Length  7.3  to  8.  mm. 

This  species  ranges  from  Canada  through  the  New  England  States 
as  far  south  as  the  District  of  Columbia,  and  west  to  Iowa  and  Lake 
Superior.  It  superficially  resembles  rather  closely  semivittatus,  but  is 
rather  smaller  and  more  obtusely  oval,  and  is  otherwise  easily  separated 
by  the  tabular  characters.  It  is  most  closely  allied  to  planatus,  which 
see  for  further  comparison  of  characters. 

A.  planatus  Shp.    On  Dytiscidae,  p.  503. 

Very  closely  related  to  the  preceding  species,  from  which  it  differs  as  follows : 
The  size  is  slightly  greater,  the  color  less  deeply  black,  but  rather  inclined  to  be 

12 


piceous,  frequently  tinged  with  rufous.  The  side  margin  of  the  prothorax  is 
sensibly  twice  as  broad  as  in  obtusatus,  and  by  this  means  the  two  may  be  readily 
separated.  The  reticulation  of  the  upper  surface  is  substantially  as  in  obtusatus, 
but  the  areolae  are  of  slightly  smaller  average  size.  The  male  tarsi  are  a  little 
more  incrassate,  the  protarsal  claws  slender,  more  elongate  and  less  curved  than 
in  obtusatus,  and  with  a  more  pronounced  angulation  at  the  extreme  base.  Length 
7.5  to  8.5  mm. 

Apparently  an  extremely  local  species,  and  aside  from  two  examples 
from  Staten  Island  in  the  Roberts  collection  it  is  known  to  me  only 
from  Marion,  Mass.,  where  on  one  occasion  it  was  taken  in  some 
numbers  by  Messrs  Bowditch,  Blanchard  and  the  writer,  in  the  nearly 
dry  bed  of  a  small  brook. 

It  may  be  well  to  remember  that  planatus  and  obtusatus  are  the  only 
species  of  Agabus  in  our  fauna  having  normally  both  postmedian  and 
apical  yellow  sub-marginal  spots.  In  stridulator  (semipunctatus  auct.) 
these  spots  are  often  seen,  but  the  greater  number  of  specimens 
in  my  series  show  no  trace  of  them. 

A.  hypomelas  Mann.     Bull.  Mosc.  II,  1843,  p.  221. 
irregularis  Mann.     Bull.  Mosc.  Ill,  1853,  p.  159. 

Oblong  oval,  piceous  or  brownish  piceous,  distinctly  aenescent;  head  in  front, 
sides  of  thorax  except  at  the  hind  angles,  and  sides  of  elytra,  diffusely  rufous; 
beneath  piceous ;  antennae,  mouth,  epipleura  and  legs,  rufous,  the  thighs  in  part 
dusky.  Head  notably  large,  prothorax  with  sides  rather  straight,  not  quite  as 
wide  at  base  as  the  base  of  the  elytra,  the  outline  therefore  somewhat  discon- 
tinuous ;  general  form  feebly  obovate,  the  maximum  width  being  at  a  little  behind 
the  middle  of  the  total  length.  Surface  reticulation  rather  fine,  the  meshes  un- 
equal, and  toward  the  sides  and  apex  exhibiting  a  secondary  system  of  minute 
reticulation.  The  usual  dorsal  series  of  punctures  are  present  on  the  elytra  to- 
gether with  numerous  minute  punctules  at  the  intersections  of  the  reticulating 
lines.  In  the  male  the  four  anterior  tarsi  are  slightly  thickened,  but  the  glandular 
hairs  of  the  lower  surface  cover  on  the  first  joint  only  a  small  apical  area.  The 
protarsal  claws  of  the  male  are  slender,  equal,  and  absolutely  simple,  and  seem 
to  be  precisely  alike  in  the  sexes.  Length  6.6  to  8.25  mm. 

Occurs  along  the  North  Pacific  Coast  from  the  Aleutian  Islands  to 
British  Columbia  and  Vancouver. 

A  well  characterized  species  which  should  be  easily  recognized, 
but  which  often  apparently  is  not,  judging  from  the  different  names 
under  which  it  appears  in  collections.  The  species  has  no  close  allies 
and  does  not  fit  in  very  smoothly  anywhere.  Because  of  a  general 
similarity  in  the  form  of  the  prosternal  process  Sharp  placed  it  in  his 
Group  2  with  seriatus  and  lugens,  while  stating  that  its  "exact  position 
is  not  easy  to  define."  Though  of  about  the  same  width  and  convexity, 
the  prosternal  process  is  rather  shorter  and  less  finely  pointed 
(acuminate)  at  tip  than  in  seriatus  and  lungens,  and  the  metasternal 
cavity  is  correspondingly  less  developed.  The  restriction  of  the 

13 


glandular  pubescence  of  the  basal  joint  of  the  protarsus  in  the  male  to 
a  small  apical  area  recalls  a  similar  condition  in  scmivittatus.  As  a 
rule  the  basal  joint  is  thus  clothed  in  about  its  apical  half. 

A.  seriatus  Say,  Trans.  Am.  Phil.  Soc.,  II,  1823,  p.  97. 
striatus  Aube.     Spec.  Gen.  1838,  p.  305. 
arctus  Melsh.     Proc.  Acad.  Phil.  II,  1846,  p.  27. 
parallelus  Lee.     Agass.  Lake  Sup.,  1850,  p.  213. 
inters ectus  Cr.     Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  419. 

Elongate  oval,  black,  aenescent,  moderately  strongly  shining,  the  occipital  and  sub- 
lateral  elytral  spots  obsolete;  mouth  and  antennae  rufous,  legs  obscure  rufous  or 
rufopiceous ;  elytral  reticulation  fairly  strong,  the  meshes  irregular  in  form ; 
minute  punctures  sparse,  and  for  the  most  part  within  the  meshes.  Front  and 
middle  tarsi  of  male  perceptibly  but  not  strongly  incrassate,  the  anterior  protarsal 
claw  not  very  strongly  arcuately  dilated  posteriorly.  Length  8  to  9.3  mm. 

This  is  one  of  the  commonest,  and  if  we  have  not  confused  two 
or  more  species  is  perhaps  the  most  widely  dispersed  of  any  in  our 
fauna.  It  is  essentially  a  northern  form,  occurring  entirely  across 
the  continent  from  Newfoundland  (Mts.  east  of  Codroy)  to  Van- 
couver, and  in  the  Rocky  Mt.  region  ranges  as  far  south  as  New 
Mexico,  and  across  the  Great  Basin  to  Nevada,  Eastern  California 
(Truckee;  Lundy)  and  Eastern  Oregon,  but  I  have  not  seen  it  from 
the  true  Pacific  fauna  south  of  Victoria  Vane.  Its  southern  limit  in  the 
East  is  a  little  uncertain.  It  is  known  to  occur  as  far  south  as 
Washington,  D.  C,  but  its  absence  from  the  southwest  Pennsylvania, 
Cincinnati  and  Iowa  lists  is  at  least  significant. 

This  species  shows  quite  a  good  deal  of  variation  in  form  and  outline. 
Parallelus  Lee.  was  based  on  one  of  the  narrower  individuals  from 
Lake  Superior;  similar  specimens  however  are  likely  to  turn  up  any- 
where within'  the  range,  and  every  possible  intermediate  is  present 
between  this  and  the  broader  examples.  For  a  like  reason  I  have 
felt  compelled  to  unite  inter sectus  Cr.  The  type  of  this  latter  (from 
Eastern  Oregon)  would  be  absolutely  lost  in  any  considerable  series 
of  seriatus  if  locality  labels  were  removed.  The  tooth  of  the  anterior 
tarsal  claw  (c?)  mentioned  by  Crotch  as  a  distinguishing  character  is 
only  a  particle  of  adhering  foreign  matter,  the  form  of  the  claw  being 
really  precisely  as  in  seriatus.  In  many  of  the  western  specimens  the 
base  of  the  prothorax  does  not  quite  equal  in  width  the  base  of  the 
elytra,  so  that  the  outline  is  less  continuous  than  in  what  we  may  call 
typical  seriatus.  The  intersectus  of  Sharp's  monograph  was  doubtless 
one  of  these  specimens.  The  size  of  these  examples,  and  in  fact  of 
western  specimens  generally  is  somewhat  less  than  of  those  from  the 
East,  but  all  differences  are  extremely  elusive  and  so  completely 
gradational  that  I  am  at  present  quite  unable  to  define  a  second  species 
in  the  extensive  material  examined. 


A.  brevicollis  Lee.  Kept.  Pac.  R.  R.  Expl.  &  Surv.  XII,  1857,  p.  34. 
Broadly  obtusely  oval  and  subdepressed ;  black,  elytra  with  or  without  a  small 
postmedian  yellow  spot  near  sides;  occipital  spots  obsolete;  antennae  rufous: 
.  legs  piceous,  the  tibiae  and  tarsi  more  or  less  obscure  rufous.  Surface  lustre  only 
moderately  shining,  the  reticulation  somewhat  rough,  meshes  unequal  and  of  ir- 
regular form,  minute  punctures  very  few,  and  when  present  within  the  meshes. 
Outline  nearly  perfectly  continuous ;  prothorax  rather  broadly  margined  at  sides ; 
metasternum  short  between  the  mesocoxae  and  coxal  plates,  the  distance  between 
them  being  less  than  one-third  the  length  of  the  latter.  Protarsi  of  male  only 
feebly  incrassate,  the  anterior  claw  a  little  dilated  toward  the  base,  very  nearly  as 
in  seriatus  and  many  lug  ens.  Length  9.8  to  n  mm. 

One  of  our  largest  species  and  apparently  not  overly  common  in 
collections,  though  seemingly  not  rare  within  its  limited  range  from 
Northern  to  Central  California.  It  is  known  to  me  from  Humboldt, 
Marin  and  Contra  Costa  Countries,  and  from  Alma  in  the  Santa  Cruz 
Mountains.  The  type  is  from  the  "upper  Sacramento  River." 

A.  lugens  Lee.    Ann.  Lye.  Nat.  Hist.  New  York,  V,  1851,  p.  203. 

sittiiralis  Cr.     Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  423. 
var.  per  plexus  Shp.     On  Dytiscidae,  p.  498. 

In  general  appearance  similar  to  and  almost  precisely  intermediate  between  the 
somewhat  larger  and  broader  brevicornis  and  the  rather  smaller  and  narrower 
seriatus.  The  color  is  black,  often  slightly  aeneous,  the  small  sublateral  yellow 
spot  of  the  elytra  usually  evident  though  often  quite  obscure, -the  antennae  darker 
rufous  or  rufopiceous,  the  legs  nearly  black.  The  elytral  reticulation  is  typically 
fine,  slightly  scabrous  toward  the  sides  and  apex,  the  small  unequal  areolae  each 
as  a  rule  with  a  single  minute  puncture.  Metasternum  between  mesocoxae  and 
coxal  plates  much  longer  than  in  the  allied  species.  Male  protarsi  moderately 
incrassate,  the  anterior  claw  varying  from  almost  perfectly  simple  (as  in  the 
type)  to  more  or  less  distinctly  arcuately  thickened  toward  the  base,  in  the  same 
fashion  as  in  seriatus  and  brevicollis,  there  being  some  degree  of  modification 
except  in  rare  instances.  Length  8.3  to  9.5  mm. 

Var.  perplexus  Shp. 

Specimens  from  Northern  California,  Washington,  Vancouver  and  British  Co- 
lumbia are,  as  a  rule,  less  finely  reticulate  than  in  typical  lugens  from  the  more 
southern  regions,  and  the  form  seems  slightly  more  obtusely  oval.  They  are  the 
perplexus  of  Sharp.  These  merge  by  insensible  gradations  into  typical  lugens, 
such  that  a  considerable  proportion,  more  especially  of  California  specimens,  are 
neither  typically  one  nor  the  other,  but  occupy  the  debatable  ground  between.  In 
the  series  before  me  of  what  I  judge  to  be  typical  perplexus,  the  length  varies 
from  9  to  9.5  mm.  In  all  males  seen  the  basal  portion  of  the  anterior  protarsal 
claw  is  a  little  thickened  precisely  as  in  the  greater  number  of  otherwise  typical 
lugens,  as  well  as  intergrading  examples. 

Lugens — including  perple.nts — is  an  extremely  common  species  in 
the  far  West,  ranging  from  British  Columbia  to  Lower  California,  and 
extending  East  to  Nevada,  Utah  (St.  George),  Arizona  (Williams; 
Chiricahua  Mts. ;  Final  Mts.),  New  Mexico  (Cloudcroft;  Silver  City; 

15 


Albuquerque;  Santa  Fe)  and  Colorado  (Canon  City;  Colorado 
Springs). 

Suturalis  Cr.,  described  from  Nevada,  differs  in  no  appreciable  way 
from  typical  lugens. 

A.  punctatus  Melsh.  Proc.  Acad.  Nat.  Sci.  Phila.,  II,  1846,  p.  27. 
Rather  obtusely  oval,  quite  strongly  convex,  rufopiceous,  margins  clearer  rufous, 
surface  usually  distinctly  aeneous;  antennae,  legs  and  epipleura  rufous.  Elytra 
minutely  reticulate  and  with  sparse  uniformly  distributed  extremely  fine  punctules, 
the  dorsal  series  of  coarser  punctures  conspicuous  but  confused ;  prothorax  with 
a  few  punctures  at  sides  except  at  the  front  angles.  Prosternal  process  elongate, 
gently  evenly  convex,  finely  margined,  the  tip  moderately  acuminate;  metaster- 
num  rather  short,  its  length  between  the  middle  coxae  and  coxal  plate  scarcely 
more  than  one-third  the  length  of  the  latter;  postero-apical  angle  of  hind  femora 
distinctly  laminate;  hind  tibiae  without  series  of  coarse  punctures  along  the  inner 
margin.  The  inner  spur  of  the  hind  tibia  is  very  long  in  both  sexes,  exceeding 
very  noticeably  the  length  of  the  first  tarsal  joint,  and  in  the  male  is  thicker, 
more  rapidly  tapering  at  tip  and  more  distinctly  striate  beneath  than  in  the  fe- 
male. Protarsal  claws  of  male  a  little  shorter  and  stouter  than  in  the  female, 
the  anterior  one  with. a  small  basal  angulation.  Length  7  to  7.25  mm. 

This  species  ranges  along  the  Atlantic  coast  from  Massachusetts 
(Nantucket)  to  Georgia.  There  are  specimens  from  Staten  Island 
and  Anglesea,  New  Jersey,  in  the  Sherman  collection.  It  is  lacking 
in  the  Washington,  D.  C.  list  but  must  occur  there.  Hamilton  gives 
it  in  the  Southwest  Pennsylvania  list,  as  does  Wickham  for  Iowa,  but 
the  latter  is  probably  in  error,  specimens  sent  me  by  Prof.  Wickham 
proving  to  be  aeruginosus. 

A.  aeruginosus  Aube,  Spec.  Gen.  1838,  p.  298. 

So  greatly  like  the  preceding  species  as  to  be  almost  inseparable  except  by  means 
of  the  male  sexual  characters,  as  indicated  in  the  table  of  species.  In  addition 
to  the  characters  there  set  forth,  it  may  be  said  that  the  middle  tibiae  of  the 
present  species  are  more  parallel  sided,  with  the  inner  fimbriate  margin  percep- 
tibly sinuate,  in  the  male,  while  in  punctatus  the  tibia  gradually  widens  from  base 
to  apex,  the  form  being  more  triangular.  In  aeruginosus  the  posterior  outline  of 
the  hind  thighs  is  evidently  concave,  and  the  apical  angle  seems  in  consequence 
distinctly  produced.  This  is  more  conspicuous  in  the  male,  but  is  also  character- 
istic in  less  degree  of  the  female,  and  with  care  offers  a  means  of  separating  the 
two  species  when  females  alone  are  present,  the  femoral  margin  in  punctatus 
being  almost  straight  or  only  very  slightly  sinuate  near  the  apical  angle.  The 
metasternum  is  even  slightly  narrower  behind  the  middle  coxa  in  aeruginosus 
than  in  punctatus.  Length  7  to  7.75  mm. 

Specimens  in  my  collection  bear  labels  Tyngsboro,  Mass.,  Lakehurst, 
New  Jersey  and  Southern  Pines,  North  Carolina,  and  this  probably 
indicates  pretty  accurately  the  range  of  the  species  in  the  Atlantic 
region.  From  the  Mississippi  Valley  I  have  seen  specimens  from 
Highland  Park  (vicinity  of  Chicago)  Illinois,  in  the  Sherman  collection, 
and  from  Iowa  City,  Iowa,  in  the  Wickham  collection.  » 

16 


In  the  long  inner  spur  of  the  hind  tibia  and  other  crural  characters 
punctatus  and  aeruginosus  differ  notably  from  all  other  known  species 
of  Agabus,  so  much  so  that  Sharp  assigned  them  to  a  separate  group 
(Group  6)  in  his  treatment  of  the  genus. 

A.  triton  new  species. 

Rather  broadly  oval,  strongly  convex,  general  color  dark  rufopiceous  or  castane- 
ous,  the  margins  more  rufous,  surface  strongly  shining  in  both  sexes.  Head 
piceous,  epistoma  and  two  vertex  spots  rufous.  Prothorax  with  rufous  sides,  the 
disk  broadly  blackish.  Elytra  with  the  disk  broadly  rufopiceous  or  dark  chestnut, 
becoming  gradually  paler  at  base  and  sides.  Body  beneath  blackish,  the  abdomen 
medio-basally  and  the  apices  of  the  segments  more  or  less  rufous.  Antennae, 
prosternum,  epipleura  and  legs  rufous,  the  femora,  especially  of  the  hind  legs, 
often  a  little  dusky.  Entire  upper  surface  finely  and  feebly  reticulate,  the  elytral 
areolae  small  and  irregular.  The  three  series  of  elytral  punctures  are  distinct 
but  considerably  confused,  and  there  is  a  system  of  scattered  minute  punctures 
occupying  the  intersections  of  the  network.  The  outline  of  the  thorax  and 
elytra  is  nearly  continuous ;  the  prosternal  process  is  of  moderate  length,  sub- 
compresso-carinate ;  the  hind  thighs  are  slightly  produced  at  their  apical  angle 
and  are  almost  destitute  of  the  stiff  bristle  bearing  erosion  at  the  angle  which  is 
so  generally  and  characteristically  present  in  this  genus;  the  hind  tibiae  have  a 
series  of  coarse  punctures  along  both  the  inner  and  outer  margins.  The  four 
anterior  tarsi  of  the  male  are  moderately  strongly  incrassate  and  clothed  beneath 
with  glandular  hairs  which  bear  rather  large  palettes.  The  claws  of  the  front 
tarsi  (d1)  are  short,  the  posterior  one  regularly  curved  and  acute  at  tip,  the  an- 
terior one  thickened  and  of  sensibly  uniform  width  from  the  basal  dilation  to  the 
obtusely  truncate  apex.  In  the  female  the  protarsal  claws  are  simple  and  like 
those  of  the  mesotarsi.  Length  6.5  to  7.5  mm.;  width  3.7  to  4.3  mm. 

Described  from  a  series  of  eight  examples  from  Edmonton,  Alberta 
(April  12,  1917 — F.  S.  Carr)  and  Winnipeg,  Manitoba  (April  17, 
1911 — J.  B.  Wallis).  The  type,  a  male  from  the  first  named  locality, 
is  in  the  writer's  collection. 

This  species  bears  a  very  striking  general  resemblance  to  punctatus, 
but  is  abundantly  distinct  in  its  greater  convexity,  compresso-convex 
prosternal  process,  inner  margin  of  hind  tibiae  punctate,  much  shorter 
posterior  tibial  spurs  and  differently  formed  anterior  protarsal  claw 
of  male. 

A.  punctulatus  Aube,  Spec.  Gen.  1838,  p.  332 

ae'neolus  Cr.  Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  417. 
Size  very  small,  form  evenly  oval ;  prothorax  piceous  with  paler  side  margins ; 
elytra  rufotestaceous  or  yellowish  brown,  the  disk  broadly  more  or  less  infuscate 
and  usually  with  distinct  aeneous  lustre ;  body  beneath  piceous,  the  antennae,  legs 
and  epipleura  rufous.  Surface  rather  finely  reticulate,  with  numerous  very  fine 
punctures  at  the  intersections  of  the  network,  the  areolae  variable  in  size  and 
form..  In  the  male  the  lustre  is  moderately  shining,  in  the  female  quite  dull, 
owing  partly  to  the  deeper  sculpture,  but  more  especially  to  a  secondary  system 
of  minute  reticulations.  The  areolae  in  the  female  are  distinctly  more  longi- 
tudinal in  the  basal  half  of  the  elytra,  not  appreciably  so-  in  the  male.  The  four 

17 


anterior  tarsi  of  the  male  are  distinctly  incrassate,  the  glandular  hairs  beneath 
bearing  minute  palettes ;  the  anterior  protarsal  claw  is  peculiarly  toothed  beneath, 
the  proximal  side  of  the  tooth  being  parallel  to,  and  the  distal  side  perpendicular 
to  the  axis  of  the  claw,  the  apex  of  the  tooth  either  rectangular  or  a  little  acute, 
and  about  twice  as  distant  from  the  base  of  the  claw  as  from  the  tip.  The  pros- 
ternal  process  is  more  narrowly  (subangularly)  convex  than  in  any  of  the  pre- 
ceding species.  Length  5.8  to  6.5  mm. 

A  species  of  northern  distribution  ranging  from  New  England  to 
Manitoba  and  perhaps  even  further  west.  Specimens  submitted  by 
Mr.  Frost  bear  the  label  "Saskatchawan?" 

This  and  the  next  are  our  smallest  species  of  Agabus.  The  present 
species  is  completely  defined  by  its  size,  color,  and  the  peculiar  form 
of  the  anterior  protarsal  claw  of  the  male.  It  is  closely  allied  to  the 
following  species,  which  has  hitherto  ben  confused  with  it. 

A.  oblongulus  new  species. 

Very  closely  allied  to  punctulatus,  the  color  similarly  aeneopiceous  with  paler 
margins,  the  elytra  varying  to  entirely  obscure  brownish  yellow ;  sculpture  nearly 
identical,  the  females  similarly  opaque ;  form  perceptibly  more  oblong,  especially 
when  series  are  compared;  tooth  of  anterior  protarsal  claw  of  male  acute  and 
more  nearly  median  in  position.  Length  5.5  to  6.3  mm. 

The  type  in  the  writer's  collection  is  a  male  from  Corvallis,  Oregon. 
I  have  also  examples  from  Port  Townsend,  Washington,  and  have 
seen  specimens  from  Spokane  Falls,  Washington  (Wickham  collection.) 

A.  semipunctatus  Kby.  Fauna  Bor.  Amer.,  Ins.  1837,  p.  69. 

stridulator  Shp.     On  Dytiscidae,  p.  509. 

Moderately  elongate,  oblong  oval;  black,  antennae  rufous,  legs  dark  rufous  the 
femora  and  sometimes  the  tibiae  darker.  Surface  moderately  shining,  without 
aeneous  lustre;  dorsal  series  of  punctures  of  elytra  conspicuous,  confused;  reticu- 
lation fine,  irregular;  minute  punctures  sparse,  sometimes  within  the  areolae, 
sometimes  at  their  intersections.  Side  margins  of  prothorax  narrow.  Third 
ventral  of  male  with  several  subparallel  rather  deep  curved  striae  each  side  of  the 
middle.  Pro-  and  mesotarsi  of  male  a  little  incrassate,  anterior  protarsal  claw 
with  an  acute  subbasal  tooth.  Length  5.5  to  6.7  mm. 

A  common  species,  occurring  over  a  large  part  of  British  America 
(Newfoundland;  Hudson  Bay  region;  Manitoba;  Alberta;  Ottawa, 
Ontario)  and  through  the  northern  United  States  from  New  England 
to  Illinois  (White  Mts.,  New  Hampshire ;  Tyngsboro,  Mass. ;  Peekskill, 
New  York;  Arlington,  New  Jersey). 

Kirby  described  from  a  unique  female  specimen,  localitv  not  stated. 
At  my  suggestion  Mr.  Arrow  has  kindly  compared  this  type  \vith 
the  type  series  of  stridulator  Shp., 'and  does  not  hesitate  to  pronounce 
them  identical.  For  some  unaccountable  reason  Sharp  seems  never 
to  have  examined  Kirby's  types  though  their  presence  in  the  British 
Museum  would  appear  to  make  them  easily  accessible  to  him. 

18 


A.  sharp!  new  species. 

In  general  aspect  almost  an  exact  counterpart  of  semipunctatus.  With  males 
in  hand  it  is  most  readily  distinguished  from  the  latter  by  the  absence  of  the 
impressed  curved  striae  of  the  third  ventral  segment.  These  striae  need  not  be 
confused  with  the  fine  scratches  present  on  the  ventral  surface  of  most  if  not  all 
species  of  Agabus,  the  latter  being  notably  finer,  and  on  the  third  segment  much 
more  transverse  in  direction.  It  may  be  further  noted  that  in  the  present  species 
the  tip  of  the  tooth  of  the  anterior  protarsal  claw  in  the  male  is  less  basal  in 
position,  being  not  much  more  distant  from  the  apex  than  from  the  base  of  the 
claw.  The  side  margin  of  the  thorax  is  much  broader  than  in  semipunctatus  and 
often  more  or  less  rufescent,  while  the  meshes  of  the  elytral  reticulation  are  dis- 
tinctly larger.  In  the  great  majority  of  females  the  elytral  sculpture  does  not 
differ  appreciably  from  that  in  the  males,  but  in  a  few  examples  is  much  deeper 
and  the  surface  lustre  comparatively  dull.  Length  6.7  to  7.1  mm. 

This  is  the  species  which  Sharp  interpreted  as  Kirby's  semipunctatus, 
and  I  have  now  before  me  a  specimen  from  the  Sharp  collection 
bearing  this  name  label  in  his  own  hand.  This  specimen  was  collected 
at  Grimsby,  Ontario  by  Pettit.  All  other  examples  seen  by  me  including 
the  type,  were  taken  at  Winnipeg,  Manitoba,  by  Mr.  J.  B.  Wallis. 
Type  in  my  own  collection. 

A.  taeniolatus  Harris,  New  Eng.  Farm.  VII,  1828,  p.  164. 

This  easily  recognizable  species  seems  to  require  no  description.  It  shares  with 
disintegratus  and  lineellus  the  distinction  of  being  the  only  gayly  colored  species 
in  our  fauna.  In  color  and  markings  of  the  upper  surface  it  is  almost  identical 
with  disintegratus,  but  the  dark  elytral  vittae  are  as  a  rule  less  distinctly  green 
bronzed  and  often  heavier  than  in  the  latter.  The  tabular  characters  are  at  all 
times  sufficient  for  the  separation  of  the  two  species,  but  it  may  be  added  that 
the  form  in  taeniolatus  is  a  little  more  broadly  oval,  the  meshes  of  the  elytral 
reticulation  a  little  smaller  and  the  minute  elytral  punctulation  more  evident, 
this  being  virtually  wanting  in  the  female  of  disintegratus,  and  almost  impercep- 
tible in  the  male.  Length  7.5  to  8  mm. 

Known  to  me  from  Massachusetts  (Tyngsboro;  Nantucket)  to 
Virginia  (Fredericksburg).  Hamilton  records  it  from  southwestern 
Pennsylvania,  and  Dury  from  Cincinnati. 

A.  disintegratus  Cr.  Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  416. 

Strikingly  similar  to  taeniolatus,  for  a  comparison  with  which  see  the  tabular 
characters  and  remarks  under  the  latter  species.  Length  7  to  7.8  mm. 

A  species  of  very  wide  distribution,  occurring  from  Massachusetts 
through  Ontario,  Canada,  to  Washington  State  (Trout  Lake)  and 
Southern  California  (Pomona).  It  is  rather  common  in  New  Jersey 
and  Pennsylvania  and  occurs  as  far  south  at  least  as  North  Carolina. 
It  is  in  the  Iowa  list  and  is  known  to  me  from  Kentucky,  St.  Louis, 
Missouri,  El  Paso,  Texas,  and  New  Mexico  (Ft.  Wingate). 

A.  lineellus  Lee.  Proc.  Acad.  Nat.  Sci.  Phila.  1861,  p.  340. 

Form  broadly  oval,  prothorax  typically  entirely  testaceous,  but  varying  to  piceous 

19 


with  the  sides  paler.  Elytra  yellow,  each  with  four  narrow  black  discal  vittae 
and  fragments  or  traces  of  one  or  two  others  external  to  these;  the  suture  also 
extremely  narrowly  margined  with  black.  Body  beneath  black;  antennae,  legs 
and  epipleura  rufous.  Elytral  reticulation  rather  lightly  impressed,  the  meshes 
large,  and  each,  as  a  rule,  with  one  or  two  very  fine  punctures.  Protarsal  claws 
of  male  rather  slender,  the  anterior  one  distinctly  but  obtusely  angulate  beneath 
at  about  the  basal  third.  Length  7.5  mm. 

This  very  rare  species  is  represented  in  the  LeConte  collection  by 
the  unique  type  taken  by  Murray  in  California,  precise  locality  not 
stated.  Aside  from  the  type  I  have  seen  only  a  single  example  collected 
by  G.  R.  Pilate  at  Mills  College,  California,  and  sent  me  for  identifica- 
tion by  Mr.  Dury,  who  retains  a  second  specimen  in  his  own  cabinet. 

A.  austini  Shp.    On  Dytiscidae,  p.  516. 

Form  varying  from  oval  to  somewhat  obovate;  above  brownish  testaceous,  the 
margins  diffusely  paler,  at  least  in  the  darker  specimens;  surface  shining,  not 
or  only  slightly  less  so  in  the  female;  beneath  piceous,  prosternum  and  abdomen 
more  or  less  paler,  legs  and  antennae  rufous,  Elytral  reticulation  coarse,  fine 
punctulation  almost  wanting.  There  is  a  minute  obscure  secondary  system  of 
reticulation  visible  only  under  considerable  amplification.  Pro-  and  mesotarsi  of 
male  narrowly  dilated,  the  glandular  hairs  tipped  with  small  rounded  palettes; 
protarsal  claws  equal,  elongate,  nearly  straight,  feebly  sinuate  on  their  lower 
edge.  Length  8.2  to  9  mm. 

A  rather  common  species  in  the  Rocky  Mountain  .and  Plateau  region, 
ranging  from  Idaho  and  New  Mexico  West  to  British  Columbia, 
Eastern  Washington  and  Eastern  California  (Truckee).  There  are 
specimens  in  the  Sherman  collection  from  Gaston,  Northwest  Oregon, 
which  is  its  closest  approach  to  the  Pacific  Coast  known  to  me.  The 
type  is  from  British  Columbia,  but  precise  locality  is  not  named. 

A.  strigulosus  Cr.    Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  422. 
nanus  Lee.     Bull.  Geol.  Surv.  IV,  1878,  p.  452. 

Narrowly  oval;  black,  head  and  thorax  slightly  bronzed;  elytra  fuscous  or 
brownish  with  margins  paler ;  legs  rufous,  hind  thighs  more  or  less  inf uscate, 
the  others  rarely  so.  Elytral  reticulation  lightly  impressed,  the  meshes  large  and 
unequal,  with  a  minute  secondary  reticulate  ground  sculpture.  Hind  thighs  with- 
out, or  with  at  most  only  a  short  basal  row  of  punctures  along  the  inner  margin. 
Pro-  and  mesotarsi  distinctly  incrassate  in  the  male,  the  glandular  hairs  tipped 
with  a  dense  mat  of  minute  palettes  anteriorly  and  with  much  larger  ones  in 
posterior  half.  Protarsal  claws  of  male  slender,  feebly  sinuate.  Length  6.2  to 
6.6  mm. 

Crotch's  type  was  from  Lake  Tahoe,  California.  Examples  are 
known  to  me  also  from  Corvallis  and  Gaston,  Oregon ;  North  Yakima, 
Washington  (Sherman  collection)  ;  Vancouver  Island  ( Wickham)  ; 
Terrace,  British  Columbia  (Mrs.  Hipplesey)  ;  Overland  Lake,  Boulder 
Co.,  Colorado  (Rohwer).  LeConte's  type  of  nanus  was  from  Floris- 
sant, Colorado,  8,000  feet. 

20 


A.  ambiguus  Say,  Trans.  Am.  Phil.  Soc.  II,  1825,  p.  96. 
reticulatus  Aube.     Spec.  Gen.  p.  355. 
fimbriatus  Lee.     Ann.  Lye.  Nat.  Hist.  N.  Y.  V,  1851,  p.  214, 

Oval,  moderately  convex,  piceous,  elytra  brownish  fuscous  with  the  limb  paler ; 
antennae  and  legs  rufous,  the  posterior  ones  often  more  or  less  infuscate;  epi- 
pleura  piceous  or  -fuscous,  concolorous  with  the  lower  surface  in  fully  colored 
specimens.  Upper  surface  very  conspicuously  irregularly  reticulate,  the  elytra 
with  secondary  minute  reticulation  or  alutaceous  sculpture,  which  is  as  a  rule 
better  denned  in  the  female;  minute  elytral  punctures  virtually  lacking.  Hind 
tibiae  with  a  series  of  a  few  punctures  along  the  inner  margin  basally.  Protarsi 
of  male  distinctly  dilated  and  densely  clothed  beneath  with  glandular  hairs  which 
bear  distinct  palettes  in  apical  half.  Length  8  to  8.3  mm. 

This  is  a  common  species  in  the  Northeastern  States.  It  ranges 
from  Canada  (Montreal)  to  Virginia  (Warm  Springs)  and  westward 
to  Dakota  (Brookings-Sherman  collection)  and  Manitoba.  The 
following  additional  specific  localities  are  represented  before  me. 
New  Hampshire  (Randolph;  Farmington)  ;  Massachusetts  (Framing- 
ham);  Pennsylvania  (Chambersburg;  Harrisburg;  Bethlehem); 
Illinois  (Vicinity  of  Chicago);  Michigan  (Marquette;  Huron  Mt. 
Club.) 

Although  not  hitherto  so  recognized,  I  have  no  doubt  whatever  that 
this  species,  commonly  known  as  reticulatus  Aube,  is  the  true  ambiguus 
of  Say.  Following  his  description,  Say  says  of  ambiguus,  "it  ap- 
proaches very  closely  to  erythropterus,  but  may  be  distinguished  by  its 
smaller  size,  less  dilated  form"  etc.  The  present  species  does  quite 
closely  resemble  erythropterus,  differing  therefrom  in  precisely  the 
ways  which  Say  indicates.  Another  highly  significant  statement  made 
by  Say  is  that  the  epipleura  are  black.  They  are  so  in  reticulatus 
Aube,  but  not  in  any  of  the  other  species  (infuscatus,  discolor,  con- 
gener) with  which  ambiguus  has  been  identified  by  later  authors.  Add 
to  this  the  fact  that  reticulatus  Aube  is  a  common  species  in  Eastern 
Pennsylvania — the  type  locality  of  ambiguus  and  that  infuscatus  and 
congener  and  probably  also  discolor  do  not  occur  there,  and  the  con- 
clusion that  ambiguus  and  reticulatus  are  one  and  the  same  species 
seems  inevitable.  By  some  oversight  fimbriatus  Lee.  is  made  a  syn- 
onym of  reticulatus  Kby  in  the  Leng  Check  List.  The  latter  is  really 
synonymous  with  arc  tic  us  Payk. 

A.  erythropterus  Say,  Trans.  Am.  Phil.  Soc.  II,  1825,  p.  95. 

The  large  size,  broad,  rather  convex  form  which  tends  to  become  somewhat 
obovate,  especially  in  the  female,  coarsely  reticulate  elytra,  the  meshes  becoming 
strongly  longitudinal  basally  in  the  female,  and  the  perfoliate  protarsal  claws  in 
the  male,  make  the  recognition  of  this  common  species  easy  and  certain.  The 
color  as  well  as  the  sculpture,  except  for  the  darker  legs  and  modified  elytral 
reticulation  in  the  female,  are  practically  the  same  as  in  ambiguus.  Males,  as 
a  rule,  are  a  little  larger  than  the  females.  Length  8.5  to  9.5  mm. 

21 


This  species  occurs  from  Cape  Breton  (Boisdale)  to  the  District  of 
Columbia,  and  westward  to  Lake  Superior.  It  is  an  abundant  species 
throughout  New  England,  New  York  and  Pennsylvania.  It  is  probable 
that  Say  described  from  Pennsylvania  specimens,  although  he  gives 
no  locality. 

A.  lutosus  Lee.  Melsh.  Cat.  1853,  p.  31. 

discolor  \\  Lee.     Ann.  Lye.  Nat.  Hist.  N.  Y.  V,  1851,  p.  204. 
lecontei  Cr.     Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  417. 

Head  and  thorax  black,  usually  with  distinct  aeneous  lustre ;  elytra  yellowish 
brown,  often  with  the  disk  more  or  less  infuscate,  sometimes  with  fuscous  irrora- 
tions;  body  beneath  black,  epipleura  yellow;  legs  and  antennae  rufous,  the  femora 
often  more  or  less  piceous.  Elytra  in  the  male  smooth  and  shining,  but  with  a 
very  fine  and  feeble  reticulation,  of  which  the  meshes  are  irregular,  some  contain- 
ing a  minute  puncture.  In  the  female  the  reticulation  is  coarse  and  deep  and  the 
surface  much  duller,  the  meshes  distinctly  longitudinal  baso-medially,  and  the 
apex,  especially  near  the  suture  becomes  much  smoother.  In  the  male  the  pro- 
tarsi  are  very  widely  dilated,  the  glandular  pubescence  beneath  bearing  quite  large 
palettes ;  anterior  protarsal  claw  with  a  conspicuous  median  acute  tooth.  Length 
7  to  8  mm. 

Lutosus  inhabits  the  Pacific  coast  region  from  Vancouver  to 
Southern  California,  and  next  to  lug  ens  is  the  commonest  species 
of  Agabus  within  that  area.  It  does  not  seem  to  extend  to  any  dis- 
tance east  of  the  Sierra  Nevadas,  but  I  have  seen  specimens  from 
Independence,  California,  on  the  western  edge  of  the  desert,  and 
from  Dalles,  Oregon.  The  type  was  taken  at  San  Francisco. 

This  species  was  described  by  LeConte  in  1851  under  the  name 
discolor,  but  this  name  being  preoccupied  by  Harris  (1828^  he  changed 
it  to  lutosus  in  his  Revision  of  the  Melsheimer  catalog  in  1853.  It 
would  seem  necessary  to  use  the  latter  name  notwithstanding  the 
fact  that  LeConte  later  inadvertently  applied  it  to  another  species.  In 
1873  Crotch  gave  it  the  name  lecontei,  and  as  such  it  has  since  been 
universally  known. 

A.  griseipennis  Lee.  Smithson.  Cont.  Knowl.  XI,  1859,  p.  5. 

Very  similar  in  structure  and  general  appearance  to  lutosus,  with  which  it  will 
probably  .be  found  confused  in  some  collections.  Males  may  be  distinguished 
from  lutosus  by  the  tabular  characters.  Females  of  the  two  species  are  greatly 
alike  and  may  not  be  separable  with  certainty  in  the  absence  of  males.  It  may 
be  said,  however,  that  except  for  specimens  taken  at  or  near  the  western  limit  of 
its  range,  the  locality  label  will  prove  a  tolerably  safe  guide  to  identification.  The 
dilation  of  the  male  tarsi  reaches  its  maximum  in  these  two  species,  and  is  even 
a  little  greater  in  griseipennis  than  in  lutosus.  Length  7.4  to  8.5  mm. 

Griseipennis  inhabits  the  Rocky  Mountain  and  Plateau  region,  at 
the  western  limit  of  which  it  comes  in  contact  with  the  territory 
occupied  by  lutosus.  It  is  rare  in  collections,  and  when  present  is 

22 


scarcely  ever  recognized.  The  following  localities  are  known  to  me. 
Wyoming  (Fort  Laramie — type)  ;  Montana  (Kalispell — Wickham)  ; 
New  Mexico  (Ft.  Wingate — Sherman  collection)  ;  Nevada  (a  male  in 
the  Sharp  collection  correctly  referred)  ;  Humboldt  Lake,  Nevada 
(Wickham  collection)  ;  Owens  Lake,  California  (G.  R.  Pilate). 

A.  nigripalpis  Sahib.  Sv.  Vet.  Ak.  Handl.  17,  4,  p.  56. 
borealis  Shp.     On  Dytiscidae,  p.  513. 
dissimilis  Sahib,  i.  litt. 

Form  elongate,  more  or  less  obovate,  especially  in  the  female ;  males  shining, 
females  sometimes  as  shining  as  the  males,  but  usually  dutler,  often  quite  opaque. 
Head,  thorax,  and  body  beneath,  black ;  elytra  varying  from  brown  to  fuscous, 
with  side  margins  more  or  less  paler,  surface  commonly  with  a  distinct  aeneous 
lustre;  legs  rufous,  the  femora  darker,  antennae  with  the  outer  joints  apically 
infuscate,  last  palpal  joint  almost  entirely  blackish.  Elytra  finely  reticulate  in 
the  male,  the  meshes  unequal  basomedially,  becoming  rather  smaller  and  nearly 
equal  toward  the  sides  and  apex ;  minute  punctulation  sparse  and  extremely  in- 
distinct, the  punctules  sometimes  within  the  meshes,  sometimes  at  the  intersec- 
tions. In  the  female  the  reticulation  is  stronger,  becoming  gradually  somewhat 
smoother  apically.  Length  of  metasternum  between  meso-coxae  and  coxal  plates 
one-half  the  length  of  the  latter.  Pro-  and  mesotarsi  quite  strongly  incrassate, 
the  glandular  hairs  tipped  with  rather  large  oblong  oval  palettes.  Protarsal 
claws  of  male  somewhat  elongate,  slender,  not  much  curved,  the  posterior  one 
sensibly  sinuate  beneath.  Length  6.5  to  6.8  mm. 

The  identification  of  the  present  species  with  the  Siberian  nigripalpis 
of  Sahlberg  is  due  I  think  to  Sharp.  This  has  been  verified  recently 
for  me  by  Mr.  Arrow,  who  writes  that  our  Arctic  American  specimens 
are  apparently  identical  with  the  type  of  borealis  Sharp,  which  latter 
Sharp  has  stated  in  his  monograph  (p.  924)  to  be  in  his  belief  the  same 
as  nigripalpis.  This  is  the  species  recorded  under  the  name  longulus 
Lee.  in  Packard's  Labrador  List. 

I  have  seen  examples  from  Stupart's  Bay  (Hudson  Bay),  and 
numerous  specimens  taken  by  the  Canadian  Arctic  Expedition  along 
the  Arctic  shores  of  British  America  and  Alaska.  In  the  report  of 
the  Canadian  Arctic  Expedition  (Part  E,  Coleoptera)  Mr.  Sherman 
quotes  the  following  localities  from  the  material  sent  him  for  deter- 
mination. Colville  Mts.,  Wollaston  Peninsula,  Victoria  Island ; 
Bernard  Harbor,  N.  W.  T.,  and  Demarcation  Point,  Barter  Island, 
Collinson  Point  and  Teller,  all  in  Alaska.  He  also  gives  Cape  Digges, 
Hudson  Strait. 

This  species  is  quite  variable  in  color,  and  on  examination  I  am 
quite  convinced  that  the  two  specimens  from  Collinson  Point  which 
Mr.  Sherman  refers  to  obsoletus  Lee.,  are  only  a  color  form  of  the 
present  species  with  yellowish  brown  elytra. 

23 


A.  morosus  Lee.  Ann.  Lye.  Nat.  Hist.  N.  Y.,  V,  1851,  p.  204. 

obsoletus  Lee.     Jour.  Acad.  Nat.  Sci.  Phila.,  (2),  IV,  1858,  p.  15. 

fossiger  Mots.     Bull.  Mosc.  Ill,  1859,  p.  170. 

Head  and  thorax  black,  the  former  with  the  usual  vertex  spots,  the  latter  with 
the  lateral  marginal  bead  only,  obscure  rufous;  elytra  dark  brown  or  brownish 
fuscous,  the  margins  more  dilute;  body  beneath  including  epipleura,  black  or 
piceous ;  labrum,  antennae  and  four  anterior  legs  rufous,  the  thighs  more  or  less 
infuscate,  hind  legs  darker.  Surface  strongly  shining  and  obsoletely  irregularly 
reticulate  in  the  male ;  in  the  female  more  coarsely  and  deeply  reticulate  and 
duller,  the  apical  fourth  (more  or  less)  of  the  elytra  rather  abruptly  much 
smoother;  minute  punctulation  scarcely  detectable.  Prosternal  process  rather 
large,  flattened  or  feebly  convex  basally,  more  convex  and  finely  acuminate 
apically.  Distance  between  meso-coxae  and  coxal  plates  distinctly  less  than  half 
the  length  of  the  latter.  Pro-  and  mesotarsi  of  male  strongly  dilated,  'the 
glandular  hairs  bearing  moderate  sized  palettes ;  protarsal  claws  elongate,  sinuate 
beneath,  their  upper  edges  straight  or  nearly  so  for  three-fourths  their  length. 
Length  6.9  to  8  mm. 

This  species  occurs  throughout  California,  the  following  localities 
being  represented  in  my  series : — San  Diego ;  Riverside ;  Pomona ;  Long 
Beach ;  San  Bernardino  Mts.,  7500  feet ;  Owens  Lake ;  San  Francisco  ; 
Humboldt  County.  The  type  is  a  female  from  San  Francisco. 

I  have  felt  constrained  to  suppress  obsoletus  Lee.  as  entirely  synony- 
mous with  the  present  species.  It  was  described  from  a  single  male 
specimen  taken  at  San  Diego,  which  harmonizes  completely  with 
males  of  morosus  from  farther  north.  The  type  of  obsoletus  carries 
no  locality  label  other  than  the  gold  disk  which  signifies  California. 
There  are  however  in  the  LeConte  series  three  other  examples — all 
?'s — with  gold  disks,  one  of  which  bears  an  additional  "Mendocino" 
label.  Two  of  these  are  typical  morosus  females ;  the  third  however 
is  much  smoother,  and  moreover  differs  in  several  slight  respects 
from  the  other  two  ?'s  and  from  the  c?  type.  Crotch's  statement  that 
the  female  in  obsoletus  is  shining  is  evidently  based  on  this  last  speci- 
men, but  it  is  certain  that  this  was  a  later  acquisition  and  there  is 
nothing  to  indicate  when  or  where  it  was  taken  or  to  connect  it 
with  the  male  type.  On  the  other  hand  I  have  perfectly  typical 
females  of  the  morosus  type  from  San  Diego  the  type  locality  of 
obsoletus,  and  have  no  doubt  of  the  correctness  of  my  conclusion  that 
these  are  one  and  the  same  species.  Among  certain  European  species 
of  Agabus  there  are  well  established  instances  of  dimorphism  in 
the  sculpture  of  the  females;  it  is  therefore  possible  that  the  smooth 
female  in  the  LeConte  series  may  be  a  variation  of  this  sort. 

A.  ancillus  new  species. 

Very  closely  related  to  morosus,  but  of  smaller  size  and  a  little  narrower,  the 
form  evenly  oblong  oval  —  often  slightly  widened  behind  in  females  of  morosus 
—  the  elytra  paler  brown  or  yellowish  brown,  the  disk  less  deeply  infuscate; 

24 


epipleura  with  pale  outer  margin;  legs  almost  entirely  rufous,  the  femoral  in- 
f uscation  feeble ;  otherwise  as  in  morosus.  Length  6.5  to  6.8  mm. 

Described  from  a  good  series  of  specimens  (Sherman  collection) 
from  Gaston  and  Corvallis,  Oregon.  The  type  is  a  male  from  the  first 
named  locality,  and  is  in  my  own  collection. 

A.  obliteratus  Lee.  Smithson.  Cont.  Knowl.  XI,  1859,  p.  5. 

Again  very  closely  related  to  morosus,  and  also  to  ancillus.  Similar  in  size  to  the 
former,  but  more  evenly  oval,  more  narrowed  in  front,  the  prothorax  conse- 
quently appreciably  smaller.  General  color  and  sculpture  nearly  as  in  morosus, 
the  elytra,  however,  are  typically  uniformly  yellow  brown,  and  as  a  rule  are  rather 
paler  than  in  that  species ;  epipleura  piceous  with  pale  outer  margin,  as  in  ancillus. 
Sexual  characters  as  in  morosus  and  ancillus.  Length  7  to  8  mm. 

Occurs  in  the  Rocky  Mountain  region  from  Wyoming  to  New  Mexico. 
I  have  seen  examples  from  Ft.  Laramie  (type)  and  Cheyenne,  Wyom- 
ing ;  Gunnison  County,  Ouray,  Georgetown,  Salida,  Denver,  and  Buena 
Vista,  Colorado;  Ft.  Wingate  and  Jemez  Springs,  New  Mexico. 

A.  congener  Payk.  Fauna  Suecica  I,  1798,  p.  214. 

Subelongate  oval,  black,  elytra  brownish  fuscous  with  dilute  margins,  upper  sur- 
face usually  feebly  aeneous ;  epipleura  and  apices  of  ventral  segments  pale ; 
antennae  rufous  with  outer  joints  partially  infuscate;  last  joints  of  palpi  more 
or  less  dusky  or  blackish  except  at  base ;  legs  rufous,  the  femora  largely  piceous. 
Elytral  reticulation  rather  fine  but  quite  distinct  under  moderate  power,  usually 
appreciably  stronger  in  the  female,  the  meshes  irregular  and  unequal  throughout  ; 
minute  punctules  sparse  and  occurring  for  the  most  part  within  the  areolae,  but 
only  detectable  upon  close  observation.  Metasternal  length  between  meso-coxae 
and  coxal  plates  unusually  great,  being  evidently  more  than  half  the  length  of  the 
latter.  Male  pro-  and  mesotarsi  rather  feebly  dilated,  the  protarsal  claws  some- 
what elongate,  slender,  little  curved  except  at  tip,  the  hinder  one  a  little  sinuate 
beneath.  Length  7.5  to  8.4  mm. 

This  species  is  evidently  abundant  in  Labrador,  judging  from  the 
nemerous  specimens  from  several  localities  received  by  Mr.  Sherman. 
It  is  also  common  according  to  Sherman  in  the  small  lakes  above 
the  tree  line  in  the  White  Mts  of  New  Hampshire.  A  single  female 
from  Ruby,  Alaska  (Kusche)  in  my  own  collection  is  here  referred 
with  some  confidence.  According  to  Sharp,  congener  is  in  Europe  a 
wide  spread  "arctic,  alpine  and  sub-alpine  species,"  and  is  there  said 
to  vary  in  color,  size  and  form,  and  extremely  so  in  the  sculpture  of 
the  female.  No  very  great  variation  of  this  sort  has  been  observed 
among  the  American  representatives  of  the  species. 

In  color  and  other  general  features  congener  is  typical  of  a  group 
of  species  between  which  it  is  more  than  usually  difficult  to  discriminate. 
These  species  have  in  consequence  been  badly  muddled  by  collectors 
and  systematists  alike.  For  instance: — Zimmermann,  in  his  recent 
paper  on  "Die  Schwimmkafer  des  Entom.  Mus.  in  Berlin-Dahlem" 

25 


places  in  synonymy  with  congener, — discolor  Harr.,  ambiguus  Say, 
fossiger  Mots.,  morosus  Lee.,  inscriptus  Cr.  and  phaeopterus  Kby. 
As  a  matter  of  fact  not  one  of  these  species  is  the  same  as  congener, 
and  they  are  for  the  most  part  mutually  distinct  among  themselves. 

A.  approximatus  new  species. 

Evenly  oval,  a  little  more  broadly  so  than  in  congener,  with  which  it  is  closely 
allied.  In  all  specimens  seen  the  elytra  are  yellowish  brown,  the  disk  much  less 
deeply  infuscate  than  is  the  rule  in  congener;  elytral  sculpture  and  lustre  not 
appreciably  different  in  the  sexes.  The  coxal  plates  are  slightly  larger  than  in 
congener,  their  distance  from  the  middle  coxae  being  about  half  their  own  length, 
this  distance  slightly  greater  in  congener;  other  differences  as  indicated  in  the 
table.  The  male  tarsi  and  tarsal  claws  are  as  in  congener.  Length  7  to  8  mm. 

Described  from  a  considerable  series  of  specimens  in  Mr.  Sherman's 
collection  bearing  label  "Horsefly  Pk.  divide,  Placerville  Rd.  San 
Mig  County,  Colorado,  8,000  feet,  July  13,  1885,"  and  were  taken  I 
think  by  either  Mr.  Hayward  or  Mr.  Bowditch.  The  type  is  a  male 
in  my  own  collection.  A  single  male  from  Florissant  Colorado 
(Cockerell)  is  also  assigned  here.  Specimens  have  more  recently 
been  received  from  Mr.  Knaus  who  took  them  at  "The  Mammouth, 
Utah,  top  of  Parowan  Mts.,  10,000  feet." 

The  present  species  is  also  very  close  to  inscriptus  and  discolor,  but 
is  quite  surely  distinct  by  its  less  minute  and  better  defined  elytral 
reticulation,  and  its  narrow  more  strongly  convex  prosternal  process ; 
the  coxal  plates  approach  the  middle  coxal  cavities  much  more  closely 
in  discolor. 

A.  discolor  Harris,  N.  E.  Farmer  VII,  1828,  p.  164. 

In  form,  color  and  general  structure,  closely  similar  to  congener,  but  separable 
with  certainty  by  the  larger  coxal  plates,  which  at  their  anterior  limits  are  less 
than  half  their  own  length  from  the  mesocoxae.  The  apices  of  the  antennal 
joints,  and  of  the  terminal  joints  of  the  palpi  are  as  a  rule  without  or  with  but 
faint  trace  of  infuscation  (distinctly  dusky  or  blackish  in  congener)  ;  the  elytral 
reticulation  is  finer  and  more  obsolete,  the  areolae  less  conspicuously  unequal, 
and  only  distinctly  so  in  the  baso-sutural  region,  becoming  nearly  equal  toward 
the  sides  and  apex.  The  size  averages  quite  distinctly  smaller  than  in  congener, 
the  larger  specimens  of  discolor  being  comparable  in  this  respect  with  the  smaller 
examples  of  the  latter,  and  the  elytra  are  oftener  of  a  clearer  and  more  uniform 
yellow  brown  color,  although  as  described  by  Harris  they  are  typically  "fuscous" 
with  "margin  and  base  pale."  The  male  tarsi  and  tarsal  claws  are  very  nearly 
as  described  of  congener.  Length  6.5  to  7.5  mm. 

This  species  ranges  from  New  England  to  Manitoba. .  The  following 
localities  have  been  noted.  Wales,  Maine  (Frost)  ;  Vermont  (Adams 
—see  below)  ;  Hopkinton,  Mass.  (Frost)  ;  Cornwall  and  Milford, 
Connecticut  (Chamberlain)  ;  Warren  and  Washington  Counties,  New 
York  (Sherman)  ;  Lake  Memphremagog,  Canada  (Dimmock)  ;  Bay- 
field,  Wisconsin  (Wickham)  ;  Isle  Royal,  Lake  Superior  (Wickham)  ; 

26 


Williston,  North  Dakota   (Wickham)  ;  Mile  332,  Hudson  Bay  R.  R. 
(Wallis). 

Under  the  number  "400,"  the  original  of  the  description  of 
"Colymbetes  discolor"  is  referred  to  in  the  Harris  Note  Book  as  having 
been  taken  "in  a  pond  May  25,  1826,"  undoubtedly  in  the  vicinity  of 
the  author's  home  in  Milton,  Mass.  This  specimen  has  disappeared 
from  the  Harris  collection  and  is  probably  no  longer  extant.  Under 
the  same  number  (400)  the  Note  Book  mentions  a  second  example 
taken  by  Adams  June  15,  1826  in  Vermont.  This  specimen  is  now 
in  the  LeConte  collection  and  as  it  is  undoubtedly  one  of  the  five 
examples  upon  which  Harris  based  his  description  I  am  accepting 
it  as  a  true  representative  of  the  species.  There  are  only  two  known 
species  occurring  in  Eastern  Massachusetts  to  which  Harris'  descrip- 
tion applies,  viz.  the  present  species  and  the  subfuscatus  of  Sharp. 
We  can  never  be  absolutely  sure  which  of  these  Harris  had  in  hand 
but  as  he  says  in  his  description  "nails  alike  in  both  sexes,"  and  this 
applies  rather  better  to  the  present  species  (though  not  strictly  true 
of  either)  than  to  subfuscatus,  I  feel  quite  confident  that  this  course 
is  the  correct  one. 

A.  inscriptus  Cr.  Trans.  Am.  Ent.  Soc.  IV,  1873,  p.  422. 

Extremely  close  to  discolor,  and  I  am  unable  to  give  any  other  means  of  separat- 
ing them  than  those  named  in  the  table.  Even  here  a  rather  nice  discrimination 
is  necessary,  though  in  practice  the  locality  label  will  usually  aid  materially.  I 
observe  that  in  the  majority  of  specimens  of  discolor  examined,  the  sides  of  the 
pronotum  are  very  narrowly  rufous  or  rufescent  within  the  marginal  bead,  while 
none  of  the  specimens  of  inscriptus  at  hand  show  this.  It  is  possible  that  this 
character  may  prove  to  have  some  value  in  a  confirmatory  way.  Length  6.4  to 
7.3  mm. 

Crotch's  type  was  from  Labrador.  According  to  Mr.  Sherman*  "it  is 
rather  common  at  Hermit  Lake,  Mt.  Washington  (3,700  feet)  but  is 
seldom  found  above  the  tree  line."  I  have  seen  an  example  from 
Sudbury,  Ontario  (Can.  Nat.  collection)  and  have  two  examples  from 
mile  332,  Hudson  Bay  R.  R.  (Wallis)  which  I  refer  here.  Mr.  Wallis 
also  took  discolor  in  the  same  locality. 

A.  canadensis  new  species. 

Of  the  same  general  appearance  as  discolor,  the  sides  of  the  thorax,  however, 
always  with  well  defined  pale  margins,  the  marginal  bead  narrower,  the  elytral 
reticulations  minute  and  subequal  throughout ;  the  very  fine  punctules  more 
numerous  and  more  easily  discernible  than  in  discolor.  The  coxal  plates  are 
nearly  as  in  discolor,  their  distance  from  the  middle  coxae  being  rather  less  than 
half  their  own  length.  Hind  tibiae  more  or  less  punctate  along  the  inner  margin 
in  basal  half  or  two-thirds.  These  punctures  vary  from  only  one  or  two  to  five  or 
six  in  number :  they  are  as  a  rule  entirely  wanting  in  discolor.  Protarsal  claws 

*A  List  of  Labrador  Coleoptera.     Jour.   N.  Y.  Ent.  Soc.  XVIII,   p.    185. 

27 


of  male  both  evidently  sinuate,  the  anterior  one  more  curved  apically.  Length 
6.7  to  7.7  mm. ;  width  3.8  to  4.2  mm. 

Of  this  species  I  have  seen  a  good  series  collected  by  Mr.  J.  B.  Wallis 
at  Winnipeg  and  Aweme,  Manitoba.  There  is  also  before  me  one 
example  labeled  "East  Ontario."  The  type  is  a  male  from  Aweme, 
and  is  in  the  writer's  collection. 

A.  subfuscatus  Shp.  On.  Dytiscidae,  p.  514. 

Of  the  same  type  as  the  several  preceding  species,  but  differing  from  them  by  the 
very  minute  and  everywhere  similar  and  virtually  equal  areolae  of  the  elytral 
reticulation.  The  minute  punctules  are  evenly  distributed  over  the  elytra  and 
are  more  easily  discernible  than  in  the  species  mentioned,  each  punctule  occupy- 
ing the  center  of  one  of  the  minute  areolae,  which  it  so  nearly  fills  as  to  preclude 
the  occurrence  of  a  second  punctule  in  the  same  area.  The  four  anterior  tarsi  of 
the  male  are,  as  in  the  preceding  species,  but  little  dilated,  but  the  protarsal  claws 
are  here  more  noticeably  modified,  the  inner  edge  of  the  anterior  claw  being  a 
little  sinuate,  while  that  of  the  posterior  claw  is  broadly,  obtusely,  but  perceptibly 
angulate  at  the  apical  third,  when  observed  from  the  proper  view  point.  This 
slight  angulation  of  the  posterior  claw  was  overlooked  by  Sharp,  but  it  is  ob- 
vious enough  on  careful  inspection  and  at  once  distinguishes  the  present  species 
from  the  numerous  similar  ones  which  are  likely  to  be  confused  with  it.  The 
elytra  are  typically  broadly  infuscate  with  paler  margins,  but  are  sometimes  of  a 
uniform  brownish  yellow  tint.  Length  7.3  to  8  mm. 

The  type  locality  is  "Massachusetts."  In  the  series  before  me  the 
following  localities  are  represented. — "New  Hampshire ;"  Lake  of  the 
Clouds,  Mt.  Washington,  New  Hampshire;  Massachusetts  (Tyngsboro 
and  Nantucket)  ;  Connecticut  (Orange)  ;  Quebec  (St.  Jean)  ;  On- 
tario (Toronto,  Ottawa  and  Belville)  ;  Michigan  (Agricultural  Col- 
lege) ;  Illinois  (Liebeck  collection). 

A.  phaeopterus  Kby.  Fauna  Bor.  Amer.,   Ins.,   1837,  p.  70. 

This  species  of  Kirby  has  never  been  certainly  recognized  by  subsequent  writers, 
though  its  identity  with  discolor,  ambiguus,  congener  and  perhaps  other  species 
has  been  suggested  at  various  times.  Thanks  to  Mr.  Arrow  I  have  been  privi- 
leged to  study  one  of  Kirby's  two  original  specimens,  and  am  thus  able  to  fix  its 
position  in  our  series.  The  meshes  of  the  elytral  reticulation  are  minute  and 
regular  as  in  subfuscatus  and  bicolor,  with  which  it  must  be  closely  associated. 
The  minute  punctulation  of  the  elytra  is  precisely  as  in  subfuscatus,  but  the  size 
is  smaller  than  in  that  species,  and  the  protarsal  claws  of  the  male  are  less  modi- 
fied, agreeing  very  nearly  in  this  respect  with  congener,  discolor  and  inscriptus. 
The  elytra  in  all  specimens  seen  show  very  little  discal  infuscation,  the  color 
being  nearly  uniformly  brown  or  yellowish  brown.  Length  6.5  to  7.3  mm. 

Kirby's  type  is  from  the  region  west  of  Hudson  Bay  "in  latitude 
54°."  Precisely  or  closely  similar  examples  have  been  seen  from 
Bayfield,  Wisconsin  (Wickham)  ;  Marquette,  Michigan  (Sherman)  ; 
Duluth,  Minn.;  Winnipeg;  mile  332  Hudson  Bay  R.  R.,  Manitoba 
(Wallis)  ;  Edmonton/Alberta  (Carr). 

28 


A.  bicolor  Kby.  Faun.  Bor.  Am.  IV,  1837,  p.  70. 
mutus  Shp.     On  Dytiscidae,  1882,  p.  513. 

Very  close  to  phaeopterus  in  size,  sculpture  and  structure,  but  easily  separated  by 
its  color  as  indicated  in  the  table.  The  coxal  plates  are  large,  the  distance  be- 
tween them  and  the  middle  coxal  cavities  being  even  a  little  less  than  in  phaeop- 
ierus,  and  quite  evidently  less  than  in  subfuscatus.  In  some  examples  there  is  a 
fairly  well  developed  series  of  punctures  along  the  inner  margin  of  the  hind 
tibiae,  these  being  almost  or  quite  lacking  in  all  specimens  of  phaeopterus  exam- 
ined, but  the  character  is  a  variable  one  and  must  be  used  with  caution.  Length 
6.8  to  8  mm. 

Kirby  described  bicolor  from  a  single  specimen  taken  in  British 
America  "in  latitude  54°."  I  have  not  seen  the  type,  but  the  descrip- 
tion, so  far  as  it  goes,  agrees  so  well  with  Sharp's  mutus,  described 
from  Hudson's  Bay,  that  I  requested  Mr.  Arrow  to  carefully  compare 
the  two  types.  He  has  done  this  and  writes  me  that  they  appear 
to  be  in  all  respects  identical.  For  a  cotype  of  mutus  from  the  Sharp 
collection  I  am  indebted  to  Mr.  Arrow ;  there  is  also  before  me  an 
example  taken  by  Mr.  Wallis  at  Mile  214  Hudson  Bay  R.  R.  and  three 
examples  (Sherman  collection)  collected  by  Mr.  F.  S.  Carr  at  Edmon- 
ton, Alberta,  which  seem  to  be  the  same  thing. 

A.  confinis  Gyll.  Insecta  Suecica  I,  1808,  p.  511. 

ovoidcus  Cr.     Tr.  Am.  Ent.  Soc.  IV,  1873,  p.  418. 
longulus  Lee.     Proc.  Am.  Phil.  Soc.  XVII,  1878,  p.  596. 

This  Northern  European  species  seems  to  be  rather  rare  with  us  and  I  have  seen 
but  few  specimens  in  our  collections.  The  color  is  of  the  congener  type,  the  very 
minute  and  regular  elytral  reticulation  and  extremely  fine  punctulation  are  nearly 
as  in  the  four  preceding  species.  The  size  is  greater  than  in  any  of  its  nearer 
allies,  but  the  species  is  most  readily  recognized  by  the  form  of  the  prosternal 
process,  which  is  strongly  laterally  compressed  so  as  to  be  acutely  carinate  along 
the  middle.  Infuscatus  possesses  nearly  the  same  structure,  but  is  readily  sep- 
arated by  the  rugose  intralinear  area  of  the  hind  coxae,  as  well  as  its  smaller  size 
and  commonly  fusco-irrorate  elytra.  Length  8.8  to  9  mm. 

This  species  occurs  in  the  latitude  of  our  Canadian  border.  The 
three  examples  before  me  bear  labels,  Bayfield,  Wisconsin  (Wickham) 
and  Duluth,  Minnesota.  LeConte's  type  of  longulus,  from  Lake 
Superior,  is  absolutely  identical. 

A.  infuscatus  Aube,  Spec.  Gen.  1838,  p.  330. 

The  acutely  carinate  prosternal  process,  and  rugose  intralinear  area  of  the  hind 
coxae,  taken  together,  are  sufficient  for  the  identification  of  this  species.  The 
color  is  in  general  of  the  congener  type,  but  the  elytra  are  of  a  rather  duller 
brownish  yellow  or  brownish  gray,  with  the  infuscation  very  often  taking  the 
form  of  a  dense  irroration  or  nebulosity  such  as  is  rather  frequently  seen  in 
lutosus,  and  occasionally  elsewhere.  The  sides  of  the  thorax  are  pale  in  all 
specimens  seen.  The  elytral  reticulation  is  minute  and  very  regular  and  without 
fine  punctulation.  The  male  protarsi  are  quite  strongly  incrassate,  the  protarsal 

29 


claws  a  little  more  elongate  and  less  curved  than  in  the  female  and  barely  per- 
ceptibly sinuate  beneath.  Length  6.5  to  8  mm. 

Labrador;  Ungava  Bay;  Hudson  Bay  R.  R.,  Manitoba   (Wallis). 
The  identity  of  this  species  is  based  on  typical  specimens  sent  to 
Mr.  Sherman  by  Oberthiir. 

A.  arcticus  Payk.    Fauna  Suecica,  1798,  p.  201. 

reticulatus  Kby.     Faun.  Bor.  Amer.  Ins.  1837,  p.  71. 
subfasciatus  Lee.     Smithson,  Misc.  Coll.  VI  (1863-1866),  p.  17. 

Narrowly  oval,  or  a  little  obovate ;  above  fuscous,  head  in  front,  thorax  with  sides 
and  transverse  median  fascia  (often  interrupted  at  middle)  and  side  margins  of 
elytra,  yellow.  Elytra  rather  coarsely  and  deeply  irregularly  reticulate  in  both 
sexes,  the  lustre  rather  dull.  The  pro-  and  mesotarsi  of  the  male  are  strongly 
incrassate,  with  very  large  nearly  circular  palettes  beneath ;  the  anterior  protarsal 
claw  angularly  dilated  before  the  base,  the  posterior  one  just  perceptibly  sinuate. 
The  flat,  slightly  longitudinally  concave  prosternal  process,  and  the  sinuate  front 
angles  of  the  thorax  in  the  female  are  characteristic.  Length  6  to  7.5  mm. 

This  species  is  very  abundant  in  Labrador.  It  is  widely  dispersed 
in  northern  Europe  and  Arctic  Siberia,  and  may  perhaps  occur  else- 
where in  Boreal  America. 

A.  ontarionis  new  species. 

Size  large,  oval,  outline  in  profile  slightly  gibbous,  the  highest  point  of  the  con- 
vexity being  a  little  in  advance  of  the  middle.  Head  and  thorax  piceous,  the 
latter  with  the  sides  narrowly  rufescent;  elytra  dark  brown  or  brownish  piceous 
with  sides  diffusely  paler;  surface  very  finely  irregularly  reticulate  basomedially, 
the  areolae  becoming  nearly  equal  at  sides  and  apex;  dorsal  series  of  punctures 
fine  and  inconspicuous;  minute  punctulation  wanting.  Prosternal  process  nar- 
row, angulate  in  cross  section;  post-coxal  length  of  metasternum  less  than  half 
that  of  the  coxal  plates;  hind  tibiae  with  a  row  of  punctures  along  the  inner 
margin.  Antennae  and  legs  rufous,  femora  a  little  darker.  Pro-  and  mesotarsi 
of  male  widely  dilated,  glandular  hairs  with  moderate  oval  palettes;  protarsal 
claws  elongate  and  similarly  sinuate  beneath.  Length  10  to  10.2  mm. 

Bellville,  Ontario   (type)  ;  Makinak,  Manitoba. 

Described  from  three  examples,  all  males,  submitted  by  Mr.  Sherman. 
Type  in  my  own  collection. 

This  is  one  of  our  largest  species.  In.  general  aspect  it  resembles 
erythropterus,  but  is  larger,  very  much  more  finely  reticulate  and  with 
different  male  claws. 

A.  ajax  new  species. 

Broadly  oval,  testaceous  or  brownish  testaceous;  head,  prothorax  and  body  be- 
neath usually  somewhat  more  rufous;  head  darker  posteriorly,  disk  of  prothorax 
with  rather  vague  transverse  median  darker  fascia.  Antennae  testaceous  with  at 
most  the  tips  lightly  infuscate;  terminal  joints  of  palpi  infuscate  apically.  Head 
and  thorax  moderately  irregularly  reticulate ;  elytra  strongly  minutely  reticulate, 
the  meshes  nearly  equal ;  minute  punctulation  lacking ;  the  usual  coarser  irregular 
serial  punctures  not  very  well  defined.  Prosternal  process  small,  acutely  com- 

30 


presso-carinate ;  middle  coxae  narrowly  separated ;  metasternal  wings  rather  nar- 
row externally,  their  width  between  the  mesocoxae  and  coxal  plates  about  one- 
third,  the  length  of  the  latter.  Hind  tibiae  with  a  row  of  punctures  along  the 
inner  margin.  Pro-  and  mesotarsi  very  broadly  dilated,  the  fourth  joint  barely 
half  as  wide  as  the  third;  protarsal  claws  of  male  elongate,  nearly  straight  and 
slightly  sinuate  beneath ;  claw  joint  dentate  beneath.  The  four  anterior  tarsi  are 
furnished  beneath  with  extremely  large  circular  palettes,  which  appear  to  rest 
directly  on  the  derm  or  in  part  to  be  supported  on  very  short  pedicels.  Length 
9.2  to  10  mm. ;  width  5.3  t*  5.7  mm. 

The  type,  in  my  own  collection,  is  a  male  from  Waghorn,  Alberta, 
from  whch  locality  I  have  seen  a  considerable  series,  the  greater  num- 
ber in  Mr.  Sherman's  collection.  A  series  of  specimens  (Sherman 
collection)  from  West  St.  Modest,  Labrador,  appear  to  be  identical 
in  every  respect  but  are  much  smaller,  being  barely  8  mm.  in  length. 

A  fine  big  species  which  bears  considerable  resemblance  to  the 
European  fuscipennis,  with  which  it  would  be  associated  in  Sharp's 
Group  19,  but  it  may  at  once  be  separated  from  that  species  and  from 
all  others  in  our  fauna  by  the  last  protarsal  joint  dentate  beneath  in  the 
male. 

A.  coxalis  Shp.    On  Dytiscidae,  1882,  p.  535. 

Broadly  oval;  head  and  thorax  flavotestaceous,  the  former  marked  with  black 
posteriorly,  the  latter  with  vague  dusky  median  transverse  divided  spot,  some- 
times wanting;  elytra  fuscotestaceous,  the  margins  yellowish;  body  beneath 
testaceous  varied  with  blackish ;  legs  and  antennae  flavo-  or  rufotestaceous. 
Elytra  minutely  regularly  reticulate,  dorsal  series  of  punctures  sub-obsolete. 
Prosternal  process  angulately  convex;  metasternal  length  between  middle  coxae 
and  coxal  plates  much  less  than  half  the  length  of  the  latter.  Pro-  and  meso- 
tarsi of  male  broadly  dilated  and  with  large  palettes  beneath;  anterior  protarsal 
claw  very  short  and  rather  stout,  posterior  claw  slender,  rather  more  than  twice 
as  long,  and  a  little  sinuate  beneath.  Length  8.2  to  8.3  mm. 

Two  specimens  are  before  me,  collected  and  donated  by  W.  S. 
McAlpine,  who  took  them  at  Homer,  Alaska,  August  7,  1911. 

Sharp  described  this  species  from  Eastern  Siberia  (Angara)  and 
Lapland.  It  has  not  before  been  recorded  from  North  America. 
Co.valis  bears  a  general  resemblance  to  aja.\~,  especially  the  smaller 
Labrador  form,  but  is  easily  separable  by  the  male  tarsal  characters. 

A.  anthracinus  Mann.  Bull.  Mosc.  1852,  II,  p.  304. 
?  scapularis  Mann.  1.  c.  p.  303. 

Moderately  elongate  oval ;  black,  head  and  thorax  aenescent,  elytra  scarcely  so ; 
marginal  bead  of  thorax  and  sides  of  elytra  at  the  humeri  more  or  less  vaguely 
rufescent.  Surface  only  moderately  shining,  the  reticulation  coarse,  deep,  and 
irregular,  the  meshes  as  large  on  the  elytra  as  on  the  thorax.  Antennae  rufous ; 
legs  dark  rufous,  the  femora  usually  darker.  Male  tarsi  strongly  incrassate  and 
bearing  beneath  large  circular  palettes;  protarsal  claws  of  male  somewhat 
elongate,  little  curved  except  at  tip,  the  anterior  a  little  less  slender  and  scarcely 
sinuate  beneath,  the  posterior  lightly  sinuate.  Length  6.8  to  8  mm. 

31 


This  common  northern  species  ranges  entirely  across  the  continent 
from  Newfoundland  to  Alaska.  From  the  intermediate  region  there 
are  specimens  before  me  or  known  to  me  from  the  White  Mts.,  New 
Hampshire;  Tyngsboro  and  Forest  Hills  (near  Boston)  Mass.;  Mar- 
•quette,  Michigan;  Three  Lakes,  Wisconsin;  Mile  214,  Hudson  Bay 
R.  R.,  Manitoba ;  Edmonton,  Alberta ;  Virginia  River,  Utah ;  McBride 
and  Frazer  River,  British  Columbia.  Mannerheim's  type  was  from 
Sitka,  as  was  also  the  type  of  his  scapularis,  which  is  without  much 
doubt  identical. 

A.  nigroaeneus  Er.  Kaf.  Mark.  Brand.,  1837,  I,  p.  157. 

Erichsoni  G.  &  H.  Cat.  Col.  1868,  II,  p.  454. 

lutosus  Cr.     Tr.  Am.  Ent.  Soc.  1873,  IV,  p.  419. 

Size  large,  oblong-oval;  black,  the  margins  sometimes  very  narrowly  and  ob- 
scurely ferruginous;  antennae,  palpi  and  anterior  legs  rufous,  middle  and  hind 
legs  darker  rufous  or  piceous.  Elytra  strongly  irregularly  reticulate,  the  meshes 
of  moderate  size  and  having  a  secondary  reticulato-alutaceous  sculpture,  more 
distinct  toward  the  apex;  dorsal  series  of  punctures  well  marked,  minute  punctu- 
ation nearly  lacking.  Prosternal  process  short,  angularly  convex;  metasternal 
sulcus  rudimentary;  metasternum  between  meso-coxae  and  coxal  plates  longer 
than  half  the  length  of  the  latter;  apical  ventral  of  male  obliquely  longitudinally 
strigose  each  side  of  the  middle.  Pro-  and  mesotarsi  of  male  distinctly  in- 
crassate,  the  palettes  of  the  glandular  pubescence  elongate,  small  and  of  oblong 
form;  protarsal  claws  of  male  of  moderate  length,  the  anterior  one  thickened 
basally,  the  posterior  one  more  slender  but  more  noticeably  sinuate  beneath. 
Length  9.3  to  u.i  mm. 

One  of  our  largest  species  and  of  wide  northerly  distribution, 
occurring  from  Labrador  and  the  New  England  States  to  British 
Columbia. 

A.  confertus  Lee.  Proc.  Acad.  Nat.  Sci.  Phila.  1861,  p.  340. 

walsinghami  Cr.  Tr.  Am.  Ent.  Soc.  IV,  1873,  p.  419. 
Evenly  oblong-oval;  black,  margins  not  or  scarcely  paler,  elytra  with  a  small 
elongate  sublateral  yellow  spot,  sometimes  quite  obscure,  but  present  in  all  speci- 
mens examined ;  antennae  and  legs  rufous,  the  latter  often  darker  in  part.  Elytra 
lightly  reticulate,  the  meshes  rather  large,  irregular  throughout,  with  a  secondary 
micro-reticulate  sculpture,  most  distinct  toward  sides  arid  apex ;  minute  punctules 
within  the  thoracic  meshes,  but  for  the  most  part  at  the  intersections  of  the 
reticulating  lines  on  the  elytra.  Prosternum  angularly  convex  in  cross  section ; 
metasternal  sulcus  very  short,  oblique  and  rudimentary.  Pro-  and  mesotarsi  of 
male  distinctly  incrassate ;  the  protarsal  claws  both  sinuate  beneath,  the  anterior 
one  a  little  more  noticeably  so.  Length  8  to  8.5  mm. 

This  species  occurs  on  the  Pacific  Coast  from  Southern  California 
(Claremont)  to  Vancouver,  a  large  majority  of  the  specimens  seen 
being  from  Northern  California  and  Oregon.  LeConte's  type  was 
from  Pont  Reyes  on  the  California  coast  just  north  of  San  Francisco. 

Confertus  superficially  looks  a  good  deal  like  lugens,  which  occurs 


in  the  same  region  ;  the  latter  however  has  a  larger  and  flatter  prosternal 
process,  a -normally  developed  metasternal  sulcus  and  a  deeper  elytral 
reticulation,  without  the  secondary  ground  sculpture. 

A.  gagates  Aube,  Spec.  Gen.  1838,  p.  306. 

Of  moderately  large  size;  broadly  oval,  black,  aenescent,  strongly  shining  in  both 
sexes;  front  of  head  and  side  margins  of  thorax  rufescent;  side  margins  of 
elytra  sometimes  feebly  so;  beneath  piceous  or  rufopiceous,  legs  and  antennae 
rufous.  Elytral  reticulation  lightly  impressed,  the  meshes  irregular  throughout, 
minute  punctules  occurring  almost  entirely  at  the  intersections  of  the  reticulating 
lines.  There  is  a  very  fine  minute  secondary  reticulation  "not  easily  visible  on  the 
disk,  but  detectable  towards  the  sides  and  apex.  Prosternal  process  rather  short 
and  broad,  steeply  roof  shaped.  Pro-  and  mesotarsi  of  male  moderately  in- 
crassate,  the  palettes  at  tips  of  glandular  hairs  very  small  or  obsolete;  protarsal 
claws  slender,  not  longer  than  in  the  female,  the  posterior  one  slightly  sinuate  be- 
neath. Length  8  to  9.2  mm. 

This  is  one  of  the  commonest  of  the  New  England  species  ana 
ranges  as  far  south  as  North  Carolina  ("L.  Ellis").  I  have  seen 
specimens  from  South  Haven,  Michigan  in  Mr.  Sherman's  collection, 
and  Sudbury,  Ontario  (Canadian  Nat.  collection),  and  LeConte  long 
ago  recorded  the  species  from  Lake  Superior.  It  is  not  given  in 
either  the  Western  Pennsylvania,  Cincinnati  or  Iowa  Lists. 

A.  tristis  Aube,  Spec.  Gen.  1838,  p.  356. 

dubius  Mann.     Bull.  Mosc.  XVI,  1843,  p.  221. 
?  subopacus  Mann.     Bull.  Mosc.  XXVI,  1853,  p.  157. 
?  atratus  Mann.     Bull.  Mosc.  XXVI,  1853,  p.  157. 

A  large  species  of  elongate  oval  form,  varying  greatly  in  color  from  yellowish 
brown  through  various  shades  of  brown  to  almost  black,  with  or  without  paler 
lateral  margins.  The  thorax  varies  from  testaceous  with  a  median  transverse 
brownish  discal  fascia  to  entirely  black,  the  intermediate  forms  having  the  lateral 
and  apical  margins,  or  the  lateral  margins  alone  more  or  less  paler.  Body  be- 
neath piceous  varied  with  rufous;  labrum,  two  vertex  spots,  antennae,  palpi  and 
legs  rufous;  the  outer  joints  of  the  antennae,  terminal  joints  of  palpi,  and  pos- 
terior legs  more  or  less  dusky  or  infuscate.  The  primary  reticulation  of  the 
upper  surface  is  rather  coarse,  the  areolae  of  the  elytra  large  and  irregular,  with 
a  tendency  in  the  females  to  become  obliquely  longitudinal  in  the  basal  half. 
Length  9^  to  10^  mm. 

This  is  strictly  a  northern  or  high  mountain  species,  and  occurs  from 
the  Aleutian  Islands  through  the  Alaskan  Peninsula  to  British  Co- 
lumbia and  the  high  Sierras  of  California  (Lake  Tahoe  fide  Crotch; 
Mt.  Kaiser,  10,000  feet,  Blaisdell).  It  is  known  to  me  also  from  high 
altitudes  in  Colorado  and  New  Mexico,  Lake  Superior,  the  White 
Mts.  of  New  Hampshire,  and  Labrador,  while  Hamilton  records  it 
from  Arctic  Siberia. 

The  anterior  protarsal  claw  of  the  male  has  at  its  base  a  more  or  less 
prominent  angulation,  feeblest  in  the  Alaskan  representatives  and  most 

33 


developed  in  those  from  California  and  New  Mexico ;  I  have  however 
been  unable  to  correlate  it  with  other  variations  in  a  way  to  define 
any  well  marked  races. 

A.  leptapsis  Lee.  Proc.  Am.  Phil.  Soc.  XVII,  1878,  p.  596. 
Allied  in  a  general  way  to  tristis,  but  somewhat  smaller  and  more  narrowed  in 
front,  the  form  in  consequence  being  more  regularly  oval.  The  color  above  is 
black  or  piceous,  the  lateral  margins  and  epipleura  not  or  only  just  perceptibly 
paler.  Antennae,  palpi  and  body  beneath  nearly  as  in  tristis.  In  the  male  the 
surface  is  shining  and  moderately  coarsely  irregularly  reticulate,  the  areolae  sub- 
elongate  baso-medially ;  in  the  female  the  elytra  are  densely  strigoso-reticulate 
and  dull,  the  areolae  very  elongate  or  sublinear  throughout.  Metasternal  length 
between  the  meso-coxae  and  coxal  plates  evidently  greater  than  half  the  length 
of  the  latter,  while  in  tristis  it  is  rather  less  than  half  the  length  of  the  coxal 
plates.  In  the  male  the  four  anterior  tarsi  are  moderately  dilated,  but  in  the 
single  male  seen,  the  tarsal  claws  are  missing  so  that  it  is  impossible  to  say  if 
they  are  furnished  with  a  basal  tooth  or  angulation  as  in  tristis.  Length  9.5  to 
9.9  mm. 

LeConte's  unique  type  of  this  very  rare  species  is  a  female  from 
Marquette,  Michigan.  Aside  from  this  I  have  seen  only  a  single 
pair  from  Sudbury,  Ontario,  the  male  in  the  Canadian  National 
collection,  the  female  in  my  own  collection. 

A.  discors  Lee.  Proc.  Acad.  Nat.  Sci.  Phila.  1861,  p.  341. 
Oblong  oval,  body  deep  black  above  and  beneath,  epipleurae  piceous  brown;  an- 
tennae and  legs  dark  rufous  to  rufopiceous.  Male  shining,  female  opaque,  the 
elytra  in  both  sexes  longitudinally  strigoso-reticulate.  Lateral  margins  of  thorax 
wide.  Metasternum  short;  intercoxal  groove  short,  rudimentary;  last  ventral 
strigose  each  side  of  the  middle  in  the  male,  as  in  nigroaeneus.  Male  pro-  and 
mesotarsi  distinctly  incrassate,  the  protarsal  claws  elongate  and  sinuate  beneath, 
the  anterior  one  slightly  stouter.  Length  10  to  10.7  mm. 

This  very  distinct  species,  one  of  the  largest  in  our  fauna,  is  most 
often  taken  in  Oregon  and  Washington,  but  I  have  seen  specimens 
from  as  far  north  as  Vancouver,  and  one  example  in  the  Roberts 
collection  is  labeled  "California."  It  seems  to  be  rather  common  at 
Corvallis,  Oregon.  LeConte's  type  was  from  "Wash.  Terr." 

A.  clavatus  Lee.  Smithson.  Cont.  to  Knowl.  XI,  1859,  p.  4. 
Elongate  oval,  brownish  yellow,  margins  of  elytra  a  little  paler,  the  head  and 
prothorax  clearer  rufotestaceous ;  abdomen  darker,  varied  with  rufopiceous; 
antennae,  palpi  and  legs  rufous,  the  outer  joints  of  the  antennae  and  the  terminal 
joints  of  palpi  in  apical  half,  piceous.  Elytra  very  finely  and  regularly  reticulate, 
with  sparse  minute  punctulation  evenly  distributed.  Prosternum  compresso- 
carinate;  metasternal  wings  narrow,  sublinear  externally;  coxal  plates  strongly 
developed,  angulate  at  their  anterior  limits,  hind  tibiae  with  or  without  a  marginal 
series  of  punctures. 

Male  characters :  antennae  compressed  and  dilated  apically,  the  last  five  joints 
forming  a  distinct  though  gradually  formed  club,  joints  8-n  excavated  basally 
beneath ;  pro-  and  mesotarsi  moderately  incrassate  furnished  beneath  with  mod- 

34 


erate  sized  palettes ;  protarsal  claws  mutually  similar,  a  little  straighter  and  feebly 
sinuate  beneath.  Length  7.5  to  7.8  mm. 

Specimens  before  me  bear  labels,  Vernon,  British  Columbia  (Wick- 
ham  collection)  ;  Edmonton,  Alberta  (Carr)  ;  Piquitenay  River  and 
Mile  214  Hudson  Bay  R.  R.,  Manitoba  (Wallis). 

LeConte's  type  was  from  the  "Loup  Fork  of  the  Platte  River," 
Nebraska. 

Carrhydrus 

New  Genus  (tribe  Agabini) 

Of  the  general  aspect  of  our  large  species  of  Ilybius ;  broadly  evenly 
oval,  the  outline  continuous.  Antennae  attaining  the  hind  angles  of 
the  thorax,  the  intermediate  joints  broader  and  somewhat  compressed 
in  the  male.  Maxillary  palpi  normal ;  penultimate  joint  of  labial  palpi 
strongly  dilated  apically,  the  distal  half  having  somewhat  the  form 
of  a  triangular  prism  with  concave  faces.  Prothorax  narrowly  mar- 
gined at  sides,  base  broadly  feebly  lobed  at  middle;  upper  surface 
minutely  reticulate.  Prosternum  strongly  carinate  throughout,  the 
intercoxal  process  narrow,  gradually  finely  acuminate  at  tip;  mesos- 
ternum  deeply  abruptly  channeled  at  summit;  metasternum  deeply 
grooved  between  the  coxae.  Coxal  plates  strongly  sinuate  on  their 
inner  margin  and  distant  by  less  than  one  third  of  their  own  length 
from  the  middle  coxae ;  metasternal  wings  narrowly  triangular.  Hind 
coxal  processes  thickened,  rather  strongly  produced  and  deflexed  away 
from  the  abdominal  surface,  their  tips  narrowly  separated.  Legs 
short  and  stout,  all  strongly  sexually  modified,  the  basal  joint  of 
middle  tarsi  of  male  suborbicular  and  extremely  large ;  hind  thighs 
with  row  of  bristles  along  the  posterior  margin  at  apical  angle ;  joints 
of  posterior  tarsi  not  lobed  at  tip,  the  terminal  joint  but  little  shorter 
than  the  two  preceding  united,  its  claws  very  unequal. 

C.  crassipes  new  species. 

Male.  Broadly  elliptic  oval,  rather  strongly  convex,  black,  feebly  shining,  the 
side  margins  obscurely  rufescent.  Head  with  labrum  and  two  vertex  spots  dull 
rufous.  Antennae,  palpi,  legs  and  prosternum  dark  rufous  to  rufopiceous, 
trunk  beneath  nearly  black.  Antennae  rather  stout,  gradually  incrassate  medially, 
joints  6-8  widest.  Prothorax  two-thirds  wider  than  long,  sides  broadly  evenly 
arcuate,  surface  very  minutely  irregularly  reticulate;  elytra  equally  minutely  but 
very  regularly  reticulate,  much  as  in  certain  species  of  Agabus  (subfuscatus, 
phaeopterus,  etc.)  and  with  an  extremely  fine  punctulation  in  addition  to  the 
somewhat  coarser  but  still  very  fine  irregular  dorsal  series  of  punctures.  Body 
beneath  finely  strigose  as  in  Ilybius.  Front  thighs  stout,  the  middle  ones  still 
more  strongly  incrassate ;  front  and  middle  tibiae  stout,  subtriangular,  the  former 
sinuately  expanded  apically,  the  latter  with  the  external  margin  straight  and 
much  longer  than  the  inner.  Front  tarsi  with  the  basal  three  joints  broadly 

35 


dilated,  densely  clothed  beneath  with  glandular  hairs  bearing  small  rounded 
palettes,  fourth  joint  scarcely  wider  than  the  fifth,  which  is  nearly  as  long  as  all 
those  preceding;  claws  equally  elongate,  the  anterior  one  nearly  straight  and 
feebly  sinuate,  the  posterior  a  little  stouter  and  slightly  curved.  Middle  tarsi 
more  strongly  modified,  the  basal  joint  greatly  developed,  convex  above,  con- 
cave beneath,  the  basal  three  joints  densely  clothed  beneath  as  before.  Hind 
tibiae  parallel  sided,  slightly  arcuate,  with  a  dense  fringe  of  erect  hairs  along  the 
entire  length  of  their  inner  margin,  the  basal  joint  of  the  tarsi  similarly  clothed, 
the  following  joints  with  shorter  erect  hair  beneath,  most  evident  on  the  terminal 
joint;  inner  claw  barely  half  the  length  of  the  outer.  Length  13.3  mm.;  width 
7.4  mm. 

The  unique  type,  now  in  my  own  collection,  was  sent  me  by  Mr.  F.  S. 
Carr,  who  took  it  at  Edmonton,  Alberta,  June  14,  1916,  "in  a  small 
stream  clinging  to  a  straw."  Mr.  Carr  writes  that  he  has  "searched 
many  miles  and  acres  of  ponds  and  sloughs  for  others,  but  in  vain." 

This  remarkable  insect,  perhaps  the  most  extraordinary  of  our 
North  American  Dytiscidae,  presents  to  the. casual  observer  much  the 
appearance  of  our  larger  Ilybii  more  especially  of  Ilybius  ater;  on 
closer  inspection  however  the  medially  thickened  antennae,  the  unique 
form  of  the  penultimate  joint  of  the  labial  palpi,  the  strongly  pro- 
duced and  deflexed  apices  of  the  hind  coxal  processes,  the  extreme 
sexual  development  of  the  middle  tarsi,  and  the  long  dense  pilosity 
•of  the  hind  tibiae  and  tarsi  (without  doubt  also  a  sexual  character) 
at  once  attest  its  structural  singularity. 

As  the  tribes  are  at  present  defined,  it  is  not  quite  clear  whether 
our  new  genus  should  enter  the  Agabini  or  Colymbetini;  there  is  in 
fact  a  disagreement  among  authors  as  to  the  precise  makeup  of  these 
tribes.  Sharp  e.  g.  includes  Ilybius  in  the  Agabini  because  it  agrees- 
with  the  other  members  of  the  tribe  in  the  smooth  side  pieces  of  the 
first  dorsal  abdominal  segment,  and  the  presence  of  a  row  of  bristles 
at  the  outer  apical  angle  of  the  hind  femora.  Zimmermann  however 
in  his  work  on  the  Dytiscidae  of  the  Berlin  Museum  places  Ilybius 
in  the  Colymbetini  on  the  basis  of  the  lobed  apices  of  the  first  four 
joints  of  the  hind  tarsi  and  the  unequal  metatarsal  claws,  disregarding 
entirely  the  dorsal  abdominal  character'  used  by  Sharp.  It  seems 
then  to  be  a  question  of  deciding  which  characters  are  of  greater 
fundamental  importance.  In  either  case  the  relative  position  of  Ilybius 
remains  unchanged.  For  obvious  reasons  I  am  unable  to  study  the 
dorsal  abdominal  segments  in  the  unique  type  of  Carrhydrus,  but 
it  possesses  the  row  of  bristles  at  the  apical  angle  of  the  hind  femora, 
so  characteristic  of  the  Agabini,  and  the  apices  of  the  metatarsal 
joints  are  not  at  all  lobed;  moreover  the  sculpture  of  the  surface  is 
quite  like  that  of  many  Agabini  and  has  no  parallel  in  any  of  our  genera 
of  Colymbetini.  I  am  therefore  at  present  inclined  to  place  Carrhy- 
drus before  Ilybius  and  to  include  both  in  the  former  tribe. 

36 


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